There are MANY important things about learning to fly. I have just gone through the whole learning process and am currently under real flight training. One Important tip ill give you mainly because it is a basic principal of flying and is very commonly misunderstood.

Climb/descent is controlles by throttle.

Speed is control by elevator.

To enter a climb, increase power, it will maintain it's own airspeed (pretty much, enough anyway) and will climb to do this. Decreas power, it will descend and maintain airspeed.

If you move the elavator to nose down it will accelerate and descend. If you nose up, it will slow down maybe climb, maybe stall.