How to draw on a Prop Screen?

Hello, I wanted to know how to draw on the display/screen of an prop, like the PC monitor, just as in gTerminal, where when its idle, it shows the pulsing input, but then when you press E on the entity, it opens a “menu” where you can input stuff, which changes the whole “display”, I guess the 2nd display, which covers up the clients screen is made with a RichText and a DTextEntry, but I mainly want to know how its done to draw the “animation” on the prop.

HERE is the youtube video of it

Thanks for the answers!

I would assume that he simply used cam.Start3D2D() in conjunction with one of the rendering hooks, or he made a custom entity that accomplishes this in the Draw() function.

it is an entity, since he can use it, but I dont know exactly yet how to draw that on an entity, since I didnt code much with entities yet, only some basic nextbots.