FF bookmarks are just an html file in your .mozilla folder (hidden folders
can be viewed by pressing Ctrl-H). You can copy it and paste it as is (it is
called bookmarks.html and it is in your profile folder under firefox, the
profile will end in .default). You can also Go to Bookmarks, Organise
Bookmarks and Backup in FF itself. I just use the file manager and copy it.
This does not keep it synced, though. For that you need to use a service
such as Xmarks. Or you can back up your home folder using something such as
Backintime (which is what I do.)