If you have just installed or have moved into a house with a Sand Filter and you have never used one before, then this will help you.

How to Backwash your Sand Filter - Simple Instructions

Important:  Always turn the pump off between moving valve handle

1. Turn your pump off at the pool main power supply
2. Press the valve handle down and turn to the backwash position
3. Turn power supply on to start the pump, the water will exit the pool via the backwash pipe/hose 
4. Keep this running until when looking at the sight glass (normally a clear bulb or clear connection pipe on valve) the water has become clear this could take up to 2-3 mins depending on the state of the pool

1. Turn power supply off
2. Press and turn the handle to the rinse position
3. Turn pump on, rinse the sand for about 20 secs
4. Turn pump off at power supply
5. Press and rotate handle back filter position
6. Turn power back on 

This should be done on average monthly or whenever the gauge goes over 100psi