Oops, ran out of time to edit.
1st, unplug the power cord and close the input and output Q.D. valves and separate the halves.
2nd, attach a 4 foot length of vinyl tubing to the drain valve & hold the end in a 5 gallon pail OR attach a longer hose and direct outside or to a floor level drain.
3rd, open the drain valve and the output valve closest to the pump. Be sure to keep the output valve above the pump. Allow the filter to drain a sufficient amount of water to make it easy to remove from under the stand.
I bought a garden hose repair kit with QD fittings and leave a vinyl hose stub on the drain valve and then just connect a garden hose to drain the filter.