Making a new game out of an old

As per the title, I'm trying to make a new game. Someone who has prepped the materials in the past has copied one of his old games and made me a GM of it so I can get at the resources but I can't figure out how to copy/paste the stuff into my own game. Can anyone give me an idea of how to do this? I need to be able to do this for the map at least but copying or trying to move it to a folder doesn't work.

Art assets such as maps are tied the original owner's account. The main way many people use is to make screen capture of sections of the map then stitch them back together in a 3rd party program such as gimp or photoshop then upload it to roll20. Just make sure you remove the grid and tokens that do not belong on the map permanently.

Oh, ok. Are there any tutorials or videos you can direct me to which I can refer to?

Some content isn't able to be copied as a measure to prevent piracy.