how do i add my new laptop to my itunes account?

Resler,

I assume you have already downloaded and installed the iTunes program. Now you just need to authorize the computer to your account.

To authorize, go to the Store menu item on the iTunes menu bar, and choose "Authorize This Computer..." as shown below.

If by any chance you don't see the menu bar ("File, Edit, View, Controls, Store, Help"), first enable it by using CTRL+B.