This is the way i smash, the jumpsmash is my fav shot but its hard to explain.
Anyway, the smash is actually simple. This is the way i play it, when i get a shot that i can smash like a short lift, i make sure that the shuttle is slightly infront of me so that i can take the shot at an angle. Once it comes to the right place, i have my weight on my back leg and transfer the weight to my front leg as i follow through with the smash.
Sorry if this doesn't make sense but its the best way i can explain