This symbol is a quarter rest.
It indicates one beat of silence. Do not play any note.
Small counting numbers are placed underneath rests.
If a rest comes after you have played a note, you must stop the note sounding. To do this, lift your finger off the fret but keep it lightly touching the string, To stop an open string sounding lightly touch it with any finger of your left hand.
Rhythm Pattern
This exercise is a combination of quarter and half rests. Lift your finger off the D note at the start of the second count. This will give you three beats of silence.
Rhythm Pattern