Talk to your parents about consulting with a criminal defense lawyer. You may qualify for a Diversion program, if your area has one.
If you can't afford a lawyer, go to court, plea "Not Guilty" and ask for a public defender (there will be a fee for this, also).
Case Number means you will be going to court. There will be court costs and fines that your parents will have to pay. Your court date will likely come in the mail.
Another letter will be in the mail - this one will be from WalMart or their lawyers. It's a Civil Demand, and is separate from the criminal charges. The amount varies by state, expect a few hundred dollars.

