If you already have a login ID and password, please login if you haven't already done so, before trying to follow these instructions 
(if you don't see your name or login ID in the blue banner, you are not logged in):
 
If your status is Expired, click on the "Select" button to purchase a new membership.  Scroll down to Accept the Terms and Conditions and click on Submit. 

If your status is Active, check the end date to see when your membership will expire.  If you are within 60 days of the end of your Active Membership you may extend for another year from the expiration date by clicking on the icon  to the right.