To get the wax off and let the next layer to stick to it, I use either a little acetone to wash the surface wax away or I just sand it. The surfboard factories buy 55 gallon drums of laminating resin and styrene wax by the 5 gallon bucket and make their own sanding resin. You add about as much wax as catalyst. Now, you can't get surfboard resin at a hardware store or a marine store. It is usually a waxed resin and it goes off reddish brown and brittle.
Surfboard resin goes off water-clear and pretty tough.
There are reasons for that, but I am gonna ignore them right now. I can do that. I do boat repairs too, and get boat resin by the drum for that. Epoxy boards and epoxy resin are a whole other thing that I'm gonna skip right now except for one thing- WEST resin sucks. Okay, you went out and got some sanding resin.