You need a computer, and then you need the specified software, usually a serial port (COM) connection. When the LED screen is finished, you can leave a data cable to lead out, plug it into the computer, open the software and modify it with the software. This software is not universal. It depends on what board the screen is made of. You can ask the manufacturer who makes the screen for a CD with software in it.

There is an LED control card in the LED display screen. General suppliers sell products with CD-ROM software. After installing the software, click Open.

Then you need to enter a password, which is provided by the general supplier.

Then find the subtitle option in the menu bar, open it, and enter what needs to be displayed.