Once the Rufus clones have split up, Left Rufus will find himself in a darkened sewer area with Goaly. He must use the items around him to build a fire to light up the room. Note that he cannot solve this puzzle until Baby Bozo spits his pacifier into the sewers, to stop Goaly from crying.
This is considerably easier than it was in the PC version, because the interaction points are already highlighted on screen. Just avoid pressing right stick (show all objects) while solving this very short puzzle.