Firefox has two files you can create: a backup format which includes extra data like tags you have assigned to bookmarks (JSON) and an older more basic export format which is compatible with multiple browsers (HTML). I suggest creating both, just in case either of them ends up getting corrupted.

These articles have the steps:

• Backup: Restore bookmarks from backup or move them to another computer
• Export: Export Firefox bookmarks to an HTML file to back up or transfer bookmarks

Once your new Firefox is set up:

• Restore Backup: Restore bookmarks from backup or move them to another computer
• If needed, Import: Import Bookmarks from an HTML file

You might also want to save a complete copy of your Firefox profile folder, which contains other files you might come to want later. These include: saved passwords and data stored by add-ons.

Windows hides your AppData folder by default, so here's a shortcut to dive down to your profile folder. Type or paste this into the Start menu search box and press Enter to open it:

%APPDATA%\Mozilla\Firefox\Profiles

If you find multiple folders there, check inside for the most recent files. For example, in the bookmarkbackups folder, you should find some recently created files.

Copy the entire profile folder onto your external drive for future reference.

Because the folder contains your browsing history and cookies, if you are concerned about the privacy of the drive, you could first clear your history and cookies in Firefox during your final cleanup, and then make the copy after that.

Thank you so much for explaining this is straight forward non-jargon! I have saved it all onto the external hard drive and just have to import to my new computer........I might be back! Huge thank you.