The Media Groups and Presentations tabs allow you to do a few things.
To make a change click on the item you would like to change and then choose Edit Selected.
Media Groups and Presentations are part of the LUNA Viewer. Media Groups act like favorites, allowing a registered user to save items into a Media Group. Media Groups can be made public or private and can also be password protected. Slide Shows can easily be made from a Media Group, and a Media Group can be copied and reorganized. In the LUNA Viewer next to a user's login is the default Media Group and a pull down menu so they can choose which Media Group is the default. Use the Browse > Media Groups to search for public Media Groups (created by other users).
Presentations are made in the Image Workspace. Presentation playback is dynamic, and they can be exported to PowerPoint. For more details on Media Groups and Presentations visit the LUNA Viewer info page.