We were advised when we picked up our van to close the Reimo roof in a particular way.... keep the side door or window open, fix the elasticated strap to pull the sides in, then pull down sharply about halfway. The sides will bellow out but will then naturally be pulled back in by the slight vacuum inside (honest). We then make sure the clear plastic front window is folded along its bottom seam before closing to stop it creasing and causing a mark. Then strap it down with the friction straps...
Hope that helps?