hi, good start
-a- please edit your title to something meaningful
-b- please put you code in the code tag
</>
-c- yes, you need to use your
boolean button = false;
like
boolean button = true;
//...
void draw(){
if ( button ) random_circles();
//...
}
void keyPressed() {
if ( key == 'h' ) button = !button;
}