To open the Bookmarks Manager, press the Alt or F10 key bring up the tool bar, and select Bookmarks. Hot key is <Control>(Mac:<Command>) <Shift> B.

Once the window is open, at the top of the page, press the button labeled Import and Backup. Select Export Bookmarks To HTML, and follow the prompts and save it to a HTML file. Copy the file to another computer. Repeat the instructions above, BUT select Import Bookmarks From HTML,

See also:

• https://support.mozilla.org/kb/restore-bookmarks-from-backup-or-move-them
• http://kb.mozillazine.org/Backing_up_and_restoring_bookmarks_-_Firefox

You can copy/transfer files like these to your current Firefox profile folder.

• bookmarks/history: backups in the bookmarkbackups folder and possibly places.sqlite if you really need the history
• other SQLite files like cookies.sqlite (cookies) and formhistory.sqlite (saved form data)
• logins.json and key3.db (decryption key) for Passwords saved in the Password Manager
• permissions.sqlite and possibly content-prefs.sqlite for Permissions and Site Preferences
• cert8.db for stored intermediate certificates (Certificate Manager)
• sessionstore.js for open tabs and pinned tabs and tab groups

You can recover more personal data.

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

You can use this button to go to the current Firefox profile folder:

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