I Can't Sync My I Tunes Purchase To My I Pod

i have a new computer that i have downloaded i tunes on, i have my  i tunes library on it. i purchased an album off i tunes store and plugged in my i pod to sync the purchase to my i pod but nothing happens. on the computer i had before when i would plug in my i pod to my computer any purchases i made in the i tunes store would automatically sync to my i pod. what can i do to get my purchases to sync either automatically or manually ?