Roll out backwash hose (if applicable) and straighten.
Place backwash handle into backwash position. Piston type will have a lock pin or will need to be twisted to unlock, dial type (multiport) valves will have a handle that may need to be pushed down before moving (continue all movement in one direction only, or you may damage the internal spider gasket). Other valves may be located under the filter with a lever to move.
Turn the pump back on.
Turn off pump again.
Return valve (or lever) back to filter position.
Turn pump back on. Release air (from the air release valve) until water dispenses and then close air valve.
Add the correct amount of D.E. to the skimmer closest to the equipment. Refer to the owners manual for the filter for manufacturer's recommended amount of D.E.