A rest is a pause in a melody when there is a break in the sound for a particular musical phrase.
Rests in a musical phrase hold silence for some number of beats, but they do not indicate a break anywhere else in the melody.
A single beat of rest is written Z.
play "G G Z G G"
A rest can be followed by a number or fraction for a different number of beats of silence.
play """ D''/2 B'/2 Z3 D''/2 B'/2 Z3 Z3/2 E''/2 G''/2 Z/2 G'' """
More about beat notation on the reference page for beats.
If you are using rests to separate notes to create a "plucky" sound, consider using staccato notation instead.