On the page you want to bookmark, do a right click in an empty area of the page. At the top of the menu, press the Star. Hot key; <Control>
(Mac: <Command>) D.

Or, Press the bookmarks Star on the toolbar. This will place a bookmark in the Unsorted Bookmarks Folder. To edit that bookmark, press the Star again.

A window will come up with the name of the page and its web address. You can edit these entries.

Next, select what bookmarks folder you want this bookmark in. If you do not see that folder, go to the far right of the Folder line, and press the down arrow.

• Clicking the star on the Navigation toolbar will bookmark the page in the "Unsorted Bookmarks" folder and the star turns blue to show that
• Bookmarks > "Bookmark This Page" (Ctrl+D) will bookmark the page in the Bookmarks Menu folder (you need to confirm that)
• "Bookmark This Page" can be accessed via the right-click context menu in the browsing area or via the Bookmarks menu in the Firefox menu button drop down or menu bar (Alt+B)
• If the URL in the current tab is bookmarked and the star is highlighted blue then click this highlighted star or use "Bookmark This Page/Edit This Bookmark" (Ctrl+D) to edit the properties of the bookmark like name and location and move the bookmark to another folder or remove the bookmark

There are three main Bookmarks folders and bookmarks can only be created in one of those folders and its sub folders.

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

• https://support.mozilla.org/kb/how-do-i-use-bookmarks

I had to enter a new folder, which I called "My Bookmarks", under the "Bookmarks Menu" and then transfer all of my folders from the 'Unsorted Bookmarks" folder to "My Bookmarks."

Just remember, when you want to create a bookmark, press the star twice.