At this point, if you can name a note on a 6 string and then find that note on the 3 string then, that's it you're sorted. Problem is:
- A 3 string has a much smaller range than a 6 string. You simply won't be able to play a lot of the higher notes on a 6 string guitar, and some of the lower ones as well.
- Standard 6 string tuning allows you to play easily in all 12 keys, that's not the case for a 3 string tuned GDG. A song tabbed in the key of Bb for example would possibly work much better if you could transpose it to G.
Range
Don't be afraid to mess with things. You can sometimes play a part of a song an octave lower and it'll sound fine.
Key
You don't always need to change key but it's an advantage to know how if you do. This is where the theory course comes in, everything from naming the notes to changing keys will be useful here. This time, instead of naming the notes by their letter names you'll name by their relative names, their number, and use that to move between guitars. The theory course and the quizzes on the FB group will help you get that sorted.