Beginners are always welcome at a circle. Simple songs are a place to start. So what can you do with three chords? First, you can play hundreds of songs. Much of the Folk, Rock and Country repertoire can be played with only three chords. You can always learn another song. So what else is there? Here are some things to explore in no particular order.
How about rhythm . Many folk songs are in 2/4 or 4/4 time. We count them 1 2, 1 2 or 1 2 3 4 to keep a steady beat. Waltz time is 3/4 counted 1 2 3, 1 2 3. We still only need three chords but there are many dance rhythms we could explore. Even more important is the idea that a steady constant rhythm is the basis of everything we play.
Maybe try finger style? Most beginners use a simple strum. Almost all lessons recommend using a pick and guitar is often only a rhythm instrument. Playing melody notes finger style seems to me to be easier than cross picking. Simple finger style patterns are all in the right hand. Any chords will sound good.
Jerry Silverman wrote, “If a blues guitarist you would be — learn to play the melody”. That is really excellent advice. Barney Kessel said you should learn to play simple songs a note a a time by ear then learn to play them all over the guitar in every key. By the time you can do that you will be playing jazz, but not like Barney.
Realize that everything on the guitar is a movable shape. Every lick, every melody, can be moved down a fret or over a string. At that does is change the key. Every chord shape is moveable if you don’t play open strings. Learn it once move it around. Use a capo if necessary.
You can explore scales. A major scale is only seven notes. Do – Re – Mi – Fa – So – La – Ti and Do. I learned the melody of many tunes, starting with Freight Train, long before I learned to play a scale. To play by ear you need to know the scale of the key that you hear so that you can know which notes to play or sing. You don’t need to play scales from sheet music. Starting with Do the next note is always two frets higher except for Mi – Fa and Ti – Do which are only one fret apart. It is very helpful to be able to play the scale of the key you are going to sing or the scale of the song you are trying to learn.
Learn to use a capo. Music theory is not just for piano students. Guitar players should know a I – IV – V from a ii – V – I. These are just the scale notes Do Re Mi expressed as numbers. Theory tells you what happens when you move a note up or down a fret, or to an adjacent string. You start by learning a chord scale, which is how to play Do Re Mi all in chords. This is easy in the key of C, needs bar chords in other keys, but is useful to understand even if you can’t play bar chords. Theory is what allows you to know what happens when you move a capo up a fret. It is always useful to understand things that you are learning to perform on the instrument.
You can do any or all of the above before you learn another chord. The chords to learn for beginners are C Dm Em F G Am Bm. That will give you thousands more songs which brings us around to the start. Sometimes you want to learn a song and to learn it you need something from this list.