I use to be able to see my book marks on the left side of my screen. can no longer set that up . WHY

"Ctrl+B" is the keyboard shortcut to toggle the Bookmarks Sidebar. "Ctrl+Shift+B" is the keyboard shortcut to toggle the Bookmarks Toolbar. "Ctrl+Shift+O" is the keyboard shortcut to Open the Library. See also: *https://support.mozilla.org/en-US/kb/use-firefox-sidebar-access-bookmarks-history-synced