To edit a collection from the My Collections page, select the pencil/edit icon:

There, you’ll be able to rename the collection, add a cover image, and more. Click on the orange bubble as shown shown above to edit the collection further.

From here, you can add or remove titles and re-sequence the order of titles. You can use drag and drop to re-sequence and highlight titles and select Remove Titles to remove. Simply select a title by clicking on the number on the far left to see the full menu of actions you can perform on those selections:

You can also access the same editing options while viewing a specific collection. On the left hand side, select Edit to change the collection’s name, summary, cover image, or to manage the titles within it by selecting Manage x Titles.