Hi, I'm not sure what happened. Usually if you click the ... and click Bookmark, Firefox displays a popup box to save the bookmark. You should be able to cancel that by either clicking a Cancel button or by tapping the Esc key (on Windows, the Esc key usually cancels most dialogs).

If Firefox opened a new window that says Library at the top, you can close that window to get back to your regular window, or switch using the Firefox Taskbar button (hover your mouse over the button and Windows should display either individual thumbnails for the various Firefox windows, or a list of titles).

Any progress so far?

Once you are back in a regular Firefox window, you can open a new tab (Ctrl+T) to access your shortcuts.

Whoops, I was assuming you meant the built-in Firefox Home / new tab page. If you are using a different page with Icons and News, it may work differently.