I Wanna See If Pico 8 Was Easy To Make And How It Was Made, Because I Want To Make My Own Fantasy Console

How much programming experience do you have? Only Zep can really say for sure how easy or hard it was, but I believe he's someone who had extensive programming experience before creating PICO-8.

If you want to get an idea for what the source code for a fantasy console might look like, TIC-80 is an open-source fantasy console with some similarities to PICO-8. You can find the code at https://github.com/nesbox/TIC-80. That's the kind of thing you'd be looking to create :).

You’ll be programming in C/C++ most likely, so stat by learning that first.

SDL2 is the standard base library for making a custom game engine: http://www.libsdl.org/

Here are the docs for embedding the Lua programming language in your project: https://www.lua.org/docs.html

Pixel Vision 8 is another alternative fantasy console, based on C# and MonoGame rather than C and SDL: https://github.com/PixelVision8/PixelVision8