Okay, first off I know that they need it for their shell, but how often do you give it to them, how do you give it to them, and where do you get this liquid calcium or whatever it is?

Is it just a solid chunk or something and the snails chew on it, do you pour it in the water per gallon so that the snails can get it from anywhere in the tank, do you just pour it close to them and hope that they get it? What's the deal?

Snails do need major calcium. You can get it in crushed coral, cuttlebone, or Kent Marine Liquid Calcium (which is what I use). There's a few others but those are the most widely used. Cuttlebone just sits in there and slowly dissolves (it might need a bit of help, sometimes I scrape mine), liquid calcium just goes into the water and is absorbed, and crushed coral I think dissolves. It's like a substrate thing if I remember correctly. Feeding snails foods that are high in calcium (kale, etc.) is also good.