A rhythm pyramid like the one below is the most basic way in which a measure of music is subdivided. For practice, you can strum the different note values on open strings, chord shapes, or muted strings. Set your metronome to 80 beats per minute (BPM), give or take, and spend a few minutes alternating between quarter, eighth, and sixteenth notes.
It’s a good idea to count out loud, like this: “1 2 3 4, 1 and 2 and 3 and 4 and, 1 e and a, 2 e and a, 3 e and a, 4 e and a,” and so on.
The following figure shows you the rest equivalents to the notes in the previous figure. As you practice strumming rhythms, place rests into your playing as well.