Look for a copy of the Apple II Reference Manual, the DOS 3.3 Reference Manual, and the Applesoft Reference Manual. If you haven't used an Apple II before, you'll need manuals. The old machines don't work like Macs and Windows. They give you no clue to what commands they will accept at any given time. There are no menus until you run an application (which may or may not offer menus). I'm sure there are online resources, but as an old-timer who learned these machines when they were new, I have no clue where they might be found. Google should be a good start. Have fun.