removing sand from filter

[irishsph]

probably a really silly question, but I would like the answer begin I begin this adventure!

I was told that I may have a broken finger or valve in my sand filter and the way to check for this is to remove the filter cover and remove all the sand.
So here's my question: Do I need to drain the pool to a level below the skimmer before I do this, or can I just shut off the pump and get to work?
Any other tips/pointers involved in this process would be most helpful. Thanks!