Hi.
First, you nee know about this:
https://ocdoc.cil.li/component:gpu#video_ram_buffers
after, you need to use the video buffer of the card to build the image.
and finally use commands of gpu 'bind' and 'bitblt' to copy the image to the monitors.
P.S.: if You want not only the image on the monitors, but also to interact with them, then you will have to use events ('event.pull' at the simplest) to find out what the user has touched on the screen. 'event.pull' will return the touch event and the address of the device where the event happened.
Good luck, and have b