To add a new favorite location select File / New Favorite from the main menu.
Drag favorite folders to reorder.
Drag folders from the Finder, other applications or the browser and slides panes to add new favorites.
Right-click on a favorite folder for more options:
Get Info: open the Information Panel for the selected folder.
Show in Finder: reveal the selected folder in the Finder.
New Favorite…: add a new favorite folder.
Delete: remove the selected folder from the favorites.
Please Note: Slides allows browsing exclusively within your favorite folders and their contents.