How would I show the players (in game, not ROBLOX) avatar on a GUI screen?

I've seen it done before, specifically in Arcane Adventures, where the player's character (in which they customize) isn't standing in a 3D space, but rather acts like a 2D GUI object.

How would I achieve a similar effect?

If more clarification is needed, just ask. I'm fine without a script, I just need a shove in the right direction (although if you could provide a script you would be a saint)

Thanks!