usually when someone on here says "wax by hand" they mean "not with a machine" and will use a foam or MF applicator to apply thin, even coats of wax on the paint surface.
It sounds to me like you are asking how to apply by using just your hands. Am I correct?
if so, the answer is simple - Just don't do it.
I've seen it done "by hand" in one of Paul Dalton's videos, but I don't understand the point. He says that wax contains an enzyme that is activated by heat (from your hand), and that somehow it makes the wax work better.
I've never used, or even seen, a wax that states that it has "heat activated enzymes" or anything similar. Besides, if such a thing did exist, you would be better off applying it by machine since that is likely to generate more heat than your hands. You're also more likely to get thin, even coats of product.