If you don't clean your board first, chances are the new wax won't properly soak into the pores of the base material. After cleaning the base, take a look at the condition of your board. Make any necessary repairs, such as filing away edge burrs, filling base scratches with P-tex, or tuning the edges. At this point, professionals will usually give the board a good base grind. Unless you are lucky enough to own the expensive belt sander usually required to grind snowboard bases, you are better off taking yours to a wax shop.
Base grinds ensure a nice, even surface.
If grinding is done incorrectly, it can cause permanent damage to your snowboard base. So, don't attempt a base grind without the proper know-how and equipment, and make sure you take your board to a reputable shop. There are two ways of applying hot wax. One is to hold the wax stick against a hot iron until it melts and drips onto the board. Simply move the iron and melting wax over the board to various places to ensure good coverage.