If you are logged on to the website, your name should be visible on the right hand side of the screen, below the banner photo. If you hover over the name, one of the options should be "Profile." Click that, and it will take you to your page.
In the "Membership Summary" box, you should see the word 'Renew" in red. Clicking that should allow you to follow the steps to renew.
If your name does not appear there, it may say "Member Login." You will have to login using your user name and password.
If you have forgotten that information, simply click "Forgot My Username/Password" and a new password will be generated for you.