You can renew your checked out items from the My Library Dashboard page when you are logged into your library account.
Here's a link to an FAQ that shows you how to log in to your library account., opens a new window
Once you are logged in, click/touch the blue button located at the top right corner. It should now display your username indicating that you are logged in. Choose Checked Out from the drop down menu.
You can now see all your checked out items and choose which to renew.