in a nut shell:
-take rock out of tank and dunk in bucket of clean SW, swoosh it around to get as much junk out of it.
-place it into a container that will 100% dark but allowing air to get in. ie: Rubbermaid with a piece of plywood over it. have powerhead in there agitating the water surface to allow origination and a heater.
-do periodic water changes blowing off and sucking up the junk that will come out of the rocks.
-keep doing this for um..... someone help me with the length of time..... was it a month??
anyways, that will get you started and there are some better instructions somewhere on here if you do a search.