1. Reference Article No. 5
USING FACE MASKS TO PREVENT COVID-19 AT PUBLIC PLACES
(Issued with Decision No. 2447/QD-BYT on September 06, 2022, by the Ministry of Health)
I. OBJECTIVE
Preventing the spread of COVID-19 in the community to adapt safely, flexibly, and control the disease effectively in the new situation.
II. BASIS FOR DEVELOPING THE GUIDELINES
1. Based on the transmission mechanism of the SARS-CoV-2 virus, which spreads directly from person to person, mainly through respiratory droplets.
2. Based on the level of infection at high-risk locations:
- Locations with a high risk of exposure to the virus.
- Locations with poor ventilation in closed spaces.
3. The use of face masks in public places is a personal preventive measure to reduce the spread of COVID-19 in the community, protecting public health, especially vulnerable groups such as those with pre-existing conditions, the elderly, immune-compromised individuals, and those with obesity.
4. Public places are understood as areas serving many people in enclosed spaces like theaters, cinemas, nightclubs, restaurants, etc., or open spaces such as stadiums, parks, streets, bus stations, etc.

2. Reference Article No. 6
1. Proper Installation of LED Lights
LED lights are designed with numerous small electronic components, so careful installation is essential. Follow the steps provided to ensure safety and maximize the product's durability. The LED components are protected by a plastic casing, but strong impacts can compromise connections, potentially leading to flickering lights or damage. A steady power supply is also critical to avoid instability or fire hazards.
Never install LED lights in areas prone to fire or lacking fire prevention measures. Always ensure proper installation, turn off the power, and wait before removing or replacing fixtures.
Avoid placing LED lights in damp areas as this can affect the electrical current and pose a risk of electrocution or fire during repairs or replacements.
2. Correct Usage and Maintenance of LED Lights
a. Usage:
- Like other light bulbs, place LED lights in dry, cool areas, and avoid direct sunlight. Do not install in fire-prone, damp areas, as this can lead to electrical issues or fire hazards. For energy efficiency and extended lifespan, turn off the lights when not in use.
- Ensure proper voltage before use.
b. Maintenance:
- Regularly clean the LED bulb with a soft cloth to ensure optimal light output. Avoid using harsh chemicals, as they can damage the bulb's circuits. Dry cloths should be used to prevent electrical hazards.
- Handle the light fixture gently during installation and cleaning to avoid damage. Be patient and precise when connecting parts to ensure safe use and extend the light's lifespan. Ensure the power supply is stable to prevent light bulb burnout.
Computers are essential for both work and leisure, enhancing productivity and becoming an indispensable part of daily life:
- They make it easier to search for learning materials.
- They store documents.
- They facilitate document sharing with friends.
- They support industry-specific software applications.
- They offer entertainment, such as music, to help relieve stress.
- They allow free communication via text and calls.
- They provide opportunities to meet new people globally.
Computers are continuously evolving in performance and aesthetics, with recent upgrades to SSD storage speeds. Their widespread use in all industries is undeniable.

3. Reference Article No. 6
Simple Computer Usage Guide
Using a computer essentially involves utilizing installed programs and software to carry out various tasks such as text editing, drawing, playing games, watching movies, or listening to music...
This guide will explain in detail the simple steps for operating a computer, focusing primarily on turning it on and off correctly, following the steps below to successfully start the device.
1. Turn on the computer
- Power on the computer
This action is similar to turning on any other electronic device. Locate the Power or On/Off button on the computer's case (the largest button at the front). Press it briefly and release; avoid pressing too hard or holding it for too long. Once the computer powers on, a green indicator light will appear.
- Power on the monitor
If the monitor is off, press the Power or On/Off button at the front of the screen.
Turn on other devices
Switch on other connected devices, such as speakers, modem, Wi-Fi router, etc. If you cannot find the power button on the front, check the back of the devices. Typically, when powered on, an indicator light will appear.
Some devices share a power outlet, so ensure the power switch is on before powering on those devices to ensure they receive power.
- Start the operating system
Each computer runs an operating system such as Windows, Linux, or Mac OS. Windows is the most commonly used. Once powered on, the computer will run a check and display the system information. If everything is functioning properly, the operating system will start automatically. The red indicator light will blink to show the hard disk is active.
Once the operating system finishes loading, icons for the programs will appear on the desktop, and you can use the mouse to interact with them. The red indicator light will turn off when the hard drive stops accessing data.
2. Using programs and applications
Each operating system may have slightly different ways of managing software, but most have a user-friendly graphical interface. To begin, familiarize yourself with the programs and applications already installed on your computer and their purposes.
The icons on the desktop represent these programs. To open a program, double-click the corresponding icon. Wait for a few moments for the program window to appear.
When you're done, exit the program by clicking the X in the top-right corner or selecting File and then Exit (Close or Quit).
3. Turning off the computer
To ensure data and system safety, follow a proper shutdown process. First, close all running programs before turning off the computer and other devices, then cut the power.
For example, if you're using Windows XP, click the Start menu in the bottom left corner, select Turn Off, and wait for the system to complete any tasks before the computer shuts down.
With these basic steps, you'll easily know how to operate a computer smoothly and independently without needing additional assistance.

4. Reference Article 7
Quick and Powerful Computer Tips
If you're a frequent computer user, check out these tips to improve your efficiency and speed while using your device.
1. Reopen a Closed Tab on Your Browser
If you've accidentally closed a tab while browsing, simply press Ctrl + Shift + T to restore it in an instant.
You can also open an incognito window to browse without saving your history by pressing Windows + Shift + N.
Additionally, use Windows + arrow keys (up, down, left, right) to quickly minimize windows to one side of your screen.
2. When Using YouTube
YouTube is a well-known video-sharing platform that most internet users are familiar with. To pause a video, press the space bar or the 'K' key. To skip back or forward 10 seconds, use the 'J' and 'L' keys, and press 'M' to mute the sound.
3. Taking Screenshots
If you need to capture your screen, press the Print Screen button on your keyboard. However, we recommend using a specialized tool like Skitch for a more professional result.
Windows does offer a basic screenshot feature, but for more advanced options and better effects, Skitch is a great free alternative.
4. Cleaning Your Computer for Better Performance
Regular maintenance is crucial if you want to keep your computer running smoothly. If you want to avoid sluggish performance caused by accumulated junk and temporary files, schedule periodic cleaning tasks.
5. Locking Your Computer Instantly
If you need to step away from your computer and don’t want anyone snooping around, especially when you're checking personal details like your bank balance or loan amounts, simply press Windows + L to lock your computer immediately.

5. Reference Article 1
How to Use a Projector
Step 1: Connect the Signal Cable
To begin connecting your projector, use a VGA cable (with identical connectors on both ends) and plug it into the VGA ports on both your computer and projector.
Note: Ensure that the cable is securely plugged in. When disconnecting, grip the connector itself rather than the cable to prevent damage.
Step 2: Connect the Power Supply
For the projector to work correctly, it needs to be connected to a power source within the 100-200V range. Avoid turning off the projector suddenly, as this can damage the lamp and reduce its lifespan. Always follow the correct startup and shutdown procedure as recommended by the manufacturer.
Step 3: Power On the Projector
To start the projector, open the lens cover (if present), switch on the rear power button (if available), and press the Power button once.
If the projector was recently powered off, wait for the cooling fan to stop before restarting it.
Step 4: Display Output on the Projector
After connecting and powering on both the projector and computer, your next step is to display the image on the projector. If no image appears, check that the cable is properly connected and that you've selected the correct input port on the projector.
Also, make sure the computer is outputting the correct signal by right-clicking on the desktop and selecting: Graphics Options > Output to Desktop. Alternatively, connect and turn on the projector before powering up your laptop.
Step 5: Using the Projector’s Controls
Depending on the positioning of the projector and screen, use the projector's control buttons to adjust the image. Common controls include:
- TILT: Adjusts the height of the projected image.
- Zoom: Resizes the image.
- Focus: Sharpens the image (some models feature Auto Focus).
By combining Zoom and Focus, you can optimize the image clarity.
Step 6: Turning Off the Projector
After using the projector, press the Power button twice to turn it off.
Note: Wait for the cooling fan to stop before unplugging the power cable to avoid damage and extend the lamp’s lifespan.

6. Reference Article 2
1. Instructions for Using the Toilet:
- Sitting posture: Sit fully on the toilet seat. Do not stand on the rim or rest your feet on the edge of the toilet.
- After using the toilet, flush to clean. If you’ve used it for a bowel movement, close the lid before flushing to avoid water splashing.
- Dispose of any trash paper into the waste bin.
- Also, ensure the spray nozzle is placed back into its original position after use.
2. Instructions for Using the Sink:
- Step 1: Rub both hands with soap (or hand wash liquid) to sanitize them.
- Step 2: Turn on the water and rinse your hands under the clean water stream.
- Step 3: Turn off the faucet and check carefully to avoid water dripping.
- Note:
+ Do not throw trash, hair, or paper into the sink to prevent clogging.
+ Avoid applying excessive force to the sink.
3. Instructions for Using the Hand Dryer:
- Step 1: Place your hands under the dryer, palms down, fingers spread. Once the airflow starts, slowly move your hands in and out multiple times.
- Step 2: Turn your palms up and repeat the motion from Step 1.
- Step 3: Rub your hands together to dry them completely.
Note: The hand dryer will automatically turn off after 60 seconds of continuous operation. To continue, remove your hands from the device and repeat the steps as necessary.

7. Reference 3
HOW TO USE A PROJECTOR IN THE CLASSROOM
1. Instructions for connecting a laptop to the projector:
- After turning on the projector, connect it using an HDMI or VGA cable:
+ If both the projector and the laptop have HDMI ports, an HDMI cable should be used (similarly for VGA).
+ If the laptop only has an HDMI port, but the projector only has a VGA port, an HDMI to VGA adapter cable should be used.
- Usually, after connecting the laptop, the projector will automatically detect the signal and display the image. If the projector doesn't recognize the signal, follow these steps:
+ Press the Input or Source button on the projector's remote control to search for compatible signals.
+ Press the Windows + P keys on the laptop and select the Duplicate mode.
2. Instructions for turning the projector on and off properly:
- To turn on: switch the power at the back of the projector (if available) and press the Power button once. Note: if the projector was recently turned off and you want to restart it, wait until the fan stops before turning it on again.
- To turn off: press the Power button twice. Wait for the fan to stop running before unplugging the power cable (to prevent damage and prolong the projector's lamp life).
3. How to use the control buttons on the projector:
Some commonly found control buttons on the projector:
- Power button: turns the projector on or off.
- TILT: adjusts the height of the projection.
- Zoom: enlarges or reduces the size of the projected image.
- Focus: sharpens the clarity of the image.

