I'm worried that by rubbing the shampoo directly over my head, I'm getting my hair tangled.
No need to panic!
You don't have to rub the shampoo directly over your hair. You could also rub it between your hands, like a soap, and then apply it!
We have a little tip too... Lean your head forward so you can really work the shampoo into the roots and spread it over your scalp. There's no need to rub it through the lengths of your hair, as they'll be washed when you rinse the shampoo off!