Help me with luna lovegood in the clocktower courtyard in the task of the..

Place the boulder along the wall where the roof is missing (just down from the bench,on the right side of the piece in the middle). Once the boulder is there, the bench will allow you to move it. Wingardium Leviosa the bench upwards to create a make shift roof (on the top). Climb up on the boulder which will allow you to climb up on the vine and step onto the bench. Walk on the bench along the roofline until you get to the front entry arch between the clock tower and the clock courtyard. Wingardium Leviosa the swamp to the ground, climb back down, place the swamp in the center of the courtyard fountain, move well away (Luna will tell you when you are far enough away), "reducto" or "incendio" the swamp, and Voila