Snow at the moment.... got my sled dog out. How can i make it easier for him? ?

My 9 month old husky shepherd cross has just resently began pulling sledges. To start with it was my brother who he pulled with ease, then my dad sat down to try stop him from running onwards but instead got pulled along at a fair speed. I was wanting to know some proper pointers on getting him sledding and the gear? Also how to do this when the snows gone? Dont worry i dont let him do it for too long but he really does enjoy it, its brilliant way of tiring him out.