The diagram shows all the possible rhythms within one beat using 16th-notes.
The noteheads are meant to be played/clapped, and the sticks without heads are supposed to be felt. I find that imagining a 16th-note groove help to lock in with the feel – as if you were practising along to your own internal drummer.
Practise each rhythm individually until you feel like you’ve got it nailed.
If you’re up for a challenge, practise them with the metronome click on the second or fourth 16th. That’s a great way to work on making your time stronger and your rhythmic placement very accurate.
Another exercise that’s good for sight-reading/rhythm/concentration practice is to randomly skip through the rhythms in time.
At first, try doing four of one rhythm (that’ll be a bar of 4/4) before randomly skipping to another box, do four more.
Work it up so you can randomly skip around but doing one box per beat.
Do this with the metronome on the second or fourth 16th…