I guess first you have to give it a try.

you learn some simple one finger chords and melodies in GF1 with Lisa.

we're all bad in the first instance and improvement is slow for many of us. probably many more than will admit to it.

you will learn the scales and chord construction and as William has explained there are many ways to construct and play the chords. He has given power chords as his example but you will also learn about triads. One finger on each of three strings. Some shapes still a difficult stretch but others quite simple. 
They can either be easy in just being shown and learn the shapes which is what we all do in the first instance. To being more difficult in why these 3 notes on the strings make these chords and how you can keep those shapes all the way up the fretboard finding chords all the way up.

the usual example given would Django Rheinhart. Lost the use of 2 fingers and relearned how to play guitar to an expert and beyond level playing with his remaining 2 fingers. 

Give it a go , find what you can and can't do and find the work around needed.

good luck

Dave