Practice playing quarter notes by setting a metronome then playing a note or chord on every beat. It’s a good idea to look at notation for a song you already know and pick out what you can see from the rhythmic notation, using the fact you already know this song well to further your understanding of the notation and vice versa.
As above, these notes can be combined with notes of other lengths to create various rhythms, so make sure you take on board what a quarter note looks and sounds like and how long it lasts so that you’re equipped to interpret and play any basic rhythm you may come across.
