itunes?

I don't get it! Shayne won an ipod nano at a swim meet and since she already had one I saved it and gave it to myself for Christmas. I also got a $25 gift card to itunes from the Tuacahn Christmas party. So I was really excited to download some 80's dance music and dance until I passed out. But I cannot figure it out. I even had one of Shayne's friends come over and get us started but now I'm trying to download the Best of Depeche Mode and it is taking forever. It also said that it would automatically charge my credit card before it downloads. Well I never put a credit card on there because I wanted to use my gift card. So I have no idea what is happening! I even bought the booklet ipod & itunes for Dummies and it didn't help. I'm a little scared and a lot confused. Help!