What exactly is a "payroll debit card", and how does it work?

I was just hired by the county for a clerical position and since I dont have my own bank account (im 16), they gave me option Bm which is a payroll debit card which is supposed to arrive in the mail in 2 weeks. What will i be able to do with this new card? How does it work?|||Your paycheck will be put onto the card. The card can then be used at stores or online to purchase stuff. They will also send you a PIN seperately so that you can make cash withdrawals at ATMs.