ADD THE FOLLOWING CODE BEFORE THE MAIN WHILE LOOP:

# Start screen
start_game = False
while not start_game:
	for event in pygame.event.get():
		if event.type == pygame.QUIT:
			sys.exit() # if the user closed the window, quit the game
		elif event.type == pygame.KEYDOWN: # if the user pressed a key
			start_game = True # start the game
		
	# Draw everything to the screen
	screen.blit(background, (0, 0))	# draw over everything on the screen now by re-drawing the background

	# Draw the instructions
	font = pygame.font.Font(None, 100)
	text = font.render("Help us clean up Texas!", 1, (255,255,255))
	textrect = text.get_rect()
	textrect.centerx, textrect.centery = area.width/2,area.height/2-100
	screen.blit(text, textrect)
	
	font = pygame.font.Font(None, 40)
	text = font.render("Click on trash to throw it away, but be careful of the wildlife!", 1, (255,255,255))
	textrect = text.get_rect()
	textrect.centerx, textrect.centery = area.width/2,area.height/2
	screen.blit(text, textrect)
	
	font = pygame.font.Font(None, 50)
	text = font.render("Press any key to start the game.", 1, (255,255,255))
	textrect = text.get_rect()
	textrect.centerx, textrect.centery = area.width/2,area.height/2+50
	screen.blit(text, textrect)
	
	pygame.display.flip() # make everything we have drawn on the screen become visible in the window