Power On Stall
Entry
No need to pull nose up very high. If the nose is too high, it will drop a lot and lose excessive altitude after stall. To avoid this, maintain the pitch slightly higher than normal climb attitude at which airspeed is decreasing gradually(about 15 degrees up). Add back pressure to keep this pitch attitude constant as airspeed decrease. Look at the horizon on the both side of the cowling to judge your attitude. Also, add right rudder as airspeed goes down to keep coordinate.
Recovery
Release back pressure gently to return to the level pitch. Wait for the airspeed to increase.
Since the power on stall is the simulation of the departure stall, the altitude you begin this maneuver is the airport elevation. During recovery, you shouldn’t go below the original altitude. If you do so, that mean you crash on the ground. You should finish this maneuver at higher altitude than you begin.