I would begin by topping the two uppermost tops. From there wait a week until you see two new tops from each spot, then i would tie down the main branches by pulling them in opposite directions and securing around the edge of your pot. From there I would start a nutrient schedule for veg (eg. 2-1-1 or 5-2-1) After a few weeks of nutes you should have a bush at this point, then either flower or top/tie down etc. for a bigger bush. Good Luck! by the way what strain?