once the area is clear, place one block in the middle of the slope just above the laser beam. then run up to where the sphere is and give it a push by placing an ice platform on the waterfall behind it. it will fall down and hit the first wall, where your third ice block should push it up and over.
at this point it should roll down, get blocked by the first ice block and get stopped in the far corner. before pushing it over, place another ice block just to the side of the triangle so that you can force it into the far corner of the slope. 