Note that Help shows as a '?' in the "3-bar" Firefox menu button drop-down list.

You can tap the Alt key or press the F10 key to show the hidden Menu Bar temporarily and access the Help menu.

You can copy files like these with Firefox closed to the current profile folder to recover specific data. Note that you should be cautious with copying SQLite database files if you previously had problems.

• bookmarks and history: places.sqlite
• bookmark backups: compressed .jsonlz4 backups in the bookmarkbackups folder
• cookies.sqlite for the cookies
• formhistory.sqlite for saved form data
• logins.json and key3.db (decryption key) for Passwords saved in the Password Manager
• cert8.db and possibly cert_override.txt for (intermediate) certificates stored in the Certificate Manager
• persdict.dat for words you added to the spelling checker dictionary
• permissions.sqlite for Permissions and possibly content-prefs.sqlite for other Site Preferences
• sessionstore.js for open tabs and pinned tabs

See also:

• https://support.mozilla.org/en-US/kb/Recovering+important+data+from+an+old+profile

You can use the button on the "Help -> Troubleshooting Information" (about:support) page to go to the current Firefox profile folder or use the about:profiles page.

• Help -> Troubleshooting Information -> Profile Directory:
  Windows: Show Folder; Linux: Open Directory; Mac: Show in Finder
• http://kb.mozillazine.org/Profile_folder_-_Firefox

OK, I found the "help". It's a left click, NOT a right click as the directions state.

Mike17 said

I am trying to retrieve bookmarks from an old Firefox profile and various "answers" tell me to R-click on the 3 horizontal lines and then choose "help".

Do you want to double-check with forum volunteers on whether the instructions you are following make sense in other respects?

I assume that you want to open the "Help -> Troubleshooting Information" (about:support) page to go the the current profile folder.

Do you want to check for orphaned profiles that aren't listed?

Do you have an "Old Firefox Data" folder on the desktop in case the Refresh feature in Firefox has been used and a new profile has been created?