Did you get a guide when you bought it? I know when i bought my TI-84 Plus i got a guide stating how to start it up.
Also i got a CD which pretty much does all the work for you. If you didn't get them i would go back to the store to recieve them. (Although as i'm thinking of it i think they were in the box.)
All i did was put the CD in, install the documents, and hook my calculator up to the computer so it could program some extra features