Chordal music is based on the notes of chords. Here is a list of chordal rhythms, most of which have been explained in this book.
Practise them as chords one at a time, over and over. Then practise combining any two of them and repeating the two together. Any rhythm shown as one chord or note filling a whole measure is meant to be joined with another rhythm. There are thousands of combinations to be made.
Although the drawings below show chords C and G, the rhythms are for any chords at all.
Two chords are all that is needed to practise the rhythms in this book. The chord chart in this book gives you the best fingering for those chords and many others.