Trick answer, it doesn't.
If you can't get the hang of the controls, perhaps you just aren't coordinated enough? Or maybe you have never played a first person shooter on the computer? Everyone I know who was played the game with me, picks up on the controls within 10-20 minutes. So just because you are on the slower side of the learning curve, don't make dozens of threads bashing what is working as intended.
If your cursor is jumping around and such, you should probably back up or change your wiimote batteries. Or maybe it's because you are locking on with A. Locking on with A will make your cursor jump around as they move and you need to position your crosshairs within the tracking box.
I believe the exact quote from my roommate was "I usually hate first person shooters on console, this is the first one I've liked playing." Then followed by him telling me to get call of duty.