Flaps allow you to make a steeper approach without increasing airspeed- all things remaining the same. Just fly around and deploy your flaps to see what happens. Use good judgement. Don't go screaming by at low level and drop full flaps into the breeze, now! Most model airplanes with props on the nose don't need flaps but are for 'fun'. Big props turning slowly can actually act as a speed brake. Sailplane folks use flaps more than others. The sailplane wings are very efficient and the designs so 'clean' that landing can be problematic at short fields and you only get one attempt! If you want to really learn to fly then get a sailplane. Have fun!