OTG connection aids in supporting peripherals such as mouse, USB, keyboard...
OTG connection on Samsung Galaxy J3 Pro as follows:
Step 1:
To connect OTG, prepare an OTG cable or USB OTG.

To connect OTG, you need to prepare an OTG cable or USB OTG.
Step 2: Plug the USB OTG (OTG cable) into the device.

Insert the USB OTG (OTG cable) into the device.
Step 3: Notification of successful connection.

Connection successful notification.
That concludes your setup process. Wishing you all success.