Just to simplify things...
Future is nothing more than clear acrylic. It's not a wax or a polish, but simply clear acrylic.
You can apply it to your model with a wide, soft brush. Future is "self-leveling", that is, it dries without brush marks. You can also airbrush it on (straight from the bottle, no thinning necessary). Cleanup of the airbrush is simply with plain old H2O (that's water to you non chemists!)
It's simple, basic, inexpensive...and it works. Great stuff.