If you bought a frozen squid, let it thaw. Rinse the squid off with cold water. Place a bowl in the sink, and while holding the squid over the bowl, grasp the head (which contains the eyes and tentacles) in one hand and the body (which is above the eyes and tentacles, and has delta wing-type triangular flaps) in your other hand.Gently twist and pull the head away from the body. The viscera will come out of the body. Some black ink may spill out. The body will now be an empty tube, and the tentacles will be attached to the entrails, which contain the ink sac. The ink sac is small (about an inch long) and doesn't contain much ink per squid. If you want to use the ink, puncture the ink sac and squeeze the contents into a small bowl with about 1/4 cup of water or vinegar.
With a sharp knife, slice the tentacles from the head just below the eyes. Discard the eyes and head/entrails. Remove the beak from the center of the tentacles. Insert your hand inside the body tube and remove the cuttlebone, which looks like a long, thin piece of clear plastic. Rinse off the body and tentacles. Some chefs say you have to remove the mottled purple skin, but you don't; it's perfectly edible and is only removed for looks.
The body tube can be sliced into "rings" or the tube can be stuffed with ground pork, cheese, bread crumbs, or other ingredients and baked or braised. The tentacles can be separated with a knife and dipped in batter and deep fried, or added to pasta sauce. You have many options at this point. As you can see, the cleaning process is very easy. It might seem a little icky at first, but once you've done it, it's not so bad.
Once you've got the squid cleaning mastered, you can try some of these recipes: