how do i import bookmarks from an exported bookmark file from another computer placed in my documents

I use Dropbox to save files on the PC and Laptop. On the PC I backup the bookmarks to a Dropbox folder. When I start up the Laptop, all saved files on my PC are automatically saved to the Laptop into a Dropbox folder. How do I import these bookmarks into Firefox on my Laptop? Or, by the same token, how do I import bookmarks from a folder containing the saved bookmarks into Firefox bookmarks?