See:

• Use bookmark folders to organize your bookmarks

• http://kb.mozillazine.org/Sorting_and_rearranging_bookmarks_-_Firefox

Problem is, I have a Macbook, and so no Control1 key

Try to use the Organize menu.

At the top of the Bookmarks Manager there are 3 buttons (Organize,Views,Import & Backup) on the toolbar next to the Back and Forward button.

• The first button is the Organize button.
• The second button is the Views button.
• The third button is the Import & Backup button.

In the left pane in the Library (Bookmarks > Organize Bookmarks) there are three main folders in the "All Bookmarks" folder ("Bookmarks Toolbar","Bookmarks Menu","Unsorted Bookmarks").

• The Bookmarks Toolbar folder stores the bookmarks that you see on the (View > Toolbars >) Bookmarks Toolbar.
• The Bookmarks Menu folder stores bookmarks that you see in the Bookmarks menu and create via "Bookmarks > Bookmark This Page" or "Bookmark This Link" in the right click context menu.
• The Unsorted Bookmarks folder stores that bookmarks that are created by clicking the star at the right end of the location bar.

You can create new folders and new bookmarks in the three main folders ("Bookmarks Toolbar","Bookmarks Menu","Unsorted Bookmarks") or their sub folders, but you can not create a new folder at the root level ("All Bookmarks").
In the Bookmarks Manager you can also create a new folder via the Organize menu.
In the Bookmarks sidebar (Ctrl+B; Cmd+B on Mac) you can do that via the right-click context menu.

Got it. Thanks very much.