Background(image) not working

[kll]

like you say,

• 4 buttons on page 0
• 1 button on page 1

so there you need a

int state = 0

void draw() {
  background(200,0,200);
  if ( state == 0 ) draw_4_buttons();
  if ( state == 1 ) draw_back_button_and_some_text();
}

and the button action must change the state variable.