First off, you do not need to scrub the live rock in saltwater. If you want to keep the life on the rock, you don't need to scrub it. However, if you don't, then it is possible that it will retain some macroalgaes which may grow to pests later on.
IMO, I would recommend scrubbing it pretty well. Take out 5g out of the curing container and pull out the rock 1 at a time and scrub it with a soft-bristle tooth brush (like used for cleaning potatos).
IMO, I would cure the rock either in tank or in a 32g Brute trash can. You may need to leave it in the container for more than 5 days. You need an ammonia, nitrite, and nitrate test kit (Seachem has good ones and you can get a pack with those three for about $26). Anyways, keep your rock curing in your container with a powerhead and a heater.
THERES MORE:
When your ammonia, nitrite, and nitrate all read 0 you are fully cured. Transfer the rock to the tank if you cured it in the container. Then check and make sure everything is still reading 0.
1 week after the readings are all 0, you can add your cleanup crew. 2 weeks after you add the cleanup crew (as long as everything still reads 0), you are okay to add your first fish. Make sure you stock your tank slowly and don't add too much. Research before adding anything to your tank.
Good luck and happy reefing!
Your friend,
Ibrakeforreefs.