Where do I access the computer?

I see people on youtube that have notepad++ open and they paste code into it then it comes up on the computer etc, What's the directory as I'm unable to find it.

Hey, if you have access to the main server files, ALL OF THEM, then go to the mods folder, computercraft folder, then lua folder, then rom folder, then programs folder, make sure you save the file in notepad++ as a lua file, its in the save options when u go to save-as. once you save it, upload it into the folder, where all the programs are. and your good!

To start the program, go on the terminal and type the program name and at the end youmight need to add .lua

Normally the folder would be like this:
c:Users[USER]appdataroaming.minecraftsaves[WORLDSAVE]
The computers are listed as separate numbered folders representing the IDs of each computer.