When you delete a presentation, it will automatically appear in the Trash bin. To locate and view your deleted presentations, go to your library and click on Trash at the bottom left corner of the Library Sidebar.
To recover deleted presentations, click on Trash and then click on More at the bottom right corner of your deck. Select Recover From Trash and the presentation will automatically appear in your library.
Note: Your presentations will remain in the trash can for 30 days. After that time, they will automatically be removed. You may also empty your trash can, however, once deleted there is no way to get your presentations back.