Present random shape, then fixed order (assignment help)

Processing
10 
int step;
 
void keyPressed() {
  if (step = 1) {
    background (255, 0, 0);
  } else if (step = 2) {
    background (0, 255, 0);
  } else if (step = 3) {
    background (0, 0, 255);
  }
}