Add water to a large stock pot (or your biggest pot available). Fill the pot about 2/3rds of the way full.
Salt the water to your personal taste.
Heat the water on high until boiling.
Carefully drop the live crab into the water. How many you add will depend on the size of your pot. You don't want them to be over crowded and there should be enough space for them to breathe and not be pressed together. Cover and reduce heat to medium and let cook for 20 minutes.
Use tongs or a hook to carefully remove the crab. They will be extremely hot. Rinse with cold water and let the crab sit for 5 to 10 minutes, allowing them to cool a little before cleaning.
Place one hand on the crab’s back and the other on the abdomen. With your thumb, pull back the abdomen flap. Then grip the two separate sides of the crab and pull up and push down at the same time.
Dump the back of the crab and the green crab guts, or “crab butter” in the trash. Pull off the mandibles and the gills and throw them out too. The gills are long, slender, and tough feeling. To me, they look a little like the garlic cloves toward the inner portion of a head of garlic, only much bigger.
Split the crab in half and then rinse it thoroughly under running water.
Take a seafood cracker and picks to crack the shells and pick the meat out. I’ve never practiced any particular way of doing this. Just try to get big chunks out instead of shredding the meat. If you don’t have seafood utensils, it’s possible to use the crab itself to get the meat. I’ve used the claws to crack the shells and the sharp tips of the legs to pick the meat out.