Place crab clusters upside down on a sheet of parchment paper. Season with half of the garlic salt and Old Bay. Try to get the seasoning into any cavities and joints.
Turn crab legs over and season with remaining garlic salt and Old Bay, again paying attention to the joints and cavities.
Add water to the bottom half of your steam pot, usually a couple inches is enough. Bring to a rolling boil over medium-high heat.
Place crab legs into steam pot and place steam pot on top of water pot. Cover with lid.