The idea is to put the horse's weight to be on the left hind leg. That's what he will use to push himself into a balanced canter transition.
You should be asking your horse to move the shoulders at an angle to the left to load on the left front and push his hindquarters in. So your torso and hands should be slightly to the left while the outside leg is a bit backwards to ask the hindquarters to move to the right. Your inside leg should be if not in normal position but a bit forward.
Your weight should be South West as if you were looking and a compass so back and outside.
As for getting in the saddle it's not very hard at all, all you do is put your left leg in the stirrup on the left side of the horse, hold the reins, but not too tightly, grab ahold of the horn or front of the saddle and pull yourself up while swinging your right leg over the horses body and into the right side stirrup..
To get the correct lead you put your weight on your opposite hip bone and squeeze more with your outside leg while slightly lifting the inside rein..