After tapping on the library you wish to explore, you will be presented with the item list page.
This will, by default, be an alphabetic list of your items by title. (Sorting can be adjusted in the apps settings).
The delete button is revealed when you swipe on an item. Deleting will not only delete the item off your app, but also in the cloud.
The red border that you see on some items represent a group. That group name is shown in bold red, in front of the author's name.
In this case, "Avatar". Groups only show up on title sorted lists, and all items within it will sort by the group name, instead of the title.
Groups can be set on the item's options tab.
Tap an item to view its details.