You ask me the proper way to mount. Let us stop while you dismount, and I will show you the usual way. It is simple work. Stand opposite Nelly's near shoulder, a foot or so away from her, and facing towards the cantle of your saddle. Gather up your snaffle reins just tight enough to feel, but not pull on her mouth, and seize a part of her mane with your left hand. Insert your toe in the stirrup, just as it hangs, using your right hand if necessary. Then seize the cantle of the saddle with your right hand, and springing from your right foot, without touching the horse's flank with your left toe, raise yourself into the stirrup, pause a moment, and then throw the leg across the horse, moving your right hand away in season. If you were shorter, you might have to spring from your foot before you could touch the cantle. As in everything else, there are other and perhaps better ways to mount, and pages can be written upon the niceties of each method. But the above suffices for the nonce. You can choose your own fashion when you have tried them all.
An active youngster, like yourself, should be able to vault into the saddle without putting the left foot into the stirrup at all. In all Continental gymnasiums, this is one of the usual exercises, on a horse-block with imitation saddle, and is an excellent practice. By all means learn it.
You do not seem to hold your reins handily, Tom. Of all the methods of holding reins I prefer the old cross-country way of a generation back, still recommended, I was pleased to see, in the very excellent article "Horse" of the edition of the "Cyclopædia Britannica" now publishing, and I fancy yet much in vogue.
The School method is different; but the School requires that the curb and snaffle shall be used for different indications or "aids" to convey the rider's meaning to the horse, and not at the same time. In ordinary saddle work it is generally convenient to employ the reins together. Gather your reins up with me. The near curb outside little finger, near snaffle between little and third fingers, off snaffle between third and middle, off curb between middle and index, all four gathered flat above index and held in place by thumb, knuckles up. Or easier, take up your snaffle by the buckle and pass the third finger of left hand between its reins; then take up the curb and pass the little, third, and middle fingers between its reins. The snaffle reins, you see, are thus inside the curb reins, each is easily reached and distinguished and you can shift hold from left hand to right, or _vice versa_, more readily than in any other way, by merely placing one hand, with fingers spread to grasp the reins, in front of the other. By having the loop of each rein hanging separate so that the free hand can seize it quickly, either can be shortened or lengthened at will, or they may be so together. Moreover, this hold affords the easiest method of changing from one to both hands and back.