When parked downhill and need to reverse uphill when you put in reverse the car rolls forwards is this right or is something not right?

Assuming you're driving a car with a manual gearbox, a reverse hill start is fairly straight-forward.

To Start with, you need to have your handbrake fully on, this will stop the car from rolling.

With your clutch pedal pushed fully down, select reverse, then gradually bring your clutch pedal up towards the biting point. Once you find this, your car will try to move. At this point take your hand brake off, and you'll start moving up the hill.

Simples