Probably on every page in the top right corner you can find this search box:
Enter the name of your book and click enter. Wait a few seconds(search was lagging for me) and your results should show up on the left.
Click the book you want to take it to it's book page. Once again, wait a few seconds until a blue/gray drop down box shows up to the right of the book title:
(Not all images are working properly on the site for me so it might look a bit different for you but the color should be the same)
Click on it and choose which shelf you want the book on.
I hope this helps!