Prepo,
Yes, you MUST put the stick into Float to snowblow. You just push the lever all the way forward, hard, until it locks in. Then you will be able to angle the snow chute with the left and right position of the stick. To keep it high enough you will have to lower the skid shoes, as Bill said. The skid shoes should be the only way you keep it over the stone. If you try to lift the blower, it will end up digging or being too high, as the tractor goes over bumps (remember it sticks out in front of the tractor and amplifies the bumps the tires see). As long as it is in float it will follow the contours of the road... unless there is some hard packed snow from driving on it. You may in this case be brave enough to put some down pressure. /forums/images/graemlins/grin.gif
With Float on the loader... you will be able to drag back only. Float in forward is useless because it just folds the loader up and lifts the front tires off the ground. I do curl the bucket all the way and level some dirt in the forward motion (with down pressure). Then float in reverse. As Bill said, float does not take out hard lumps. You will need down pressure until the stone is loosened up.
Before you know it your hand will do all the work and you won't even think about what lever you are pulling!