Getting Started
Go to the Mozilla Firefox site and download the application. From there install it.
The Process
Now with Firefox 3 there is a utility built into it now to make backups and import a backed up HTML bookmark file. So to start this process load up Firefox. From there Select Bookmarks and choose the Organize option. Here you will see the start of the process. When you first see this window it should be empty.

Now here you see here the option to Import and Backup. So select that and choose Import.

Now you will see the wizard come up.

Here i have selected to just import a file for the purpose of this guide. Now click okay and navigate to the spot where you have your HTML backup file located.

That will import your bookmarks under the general bookmark folder. From here you can drag and drop the files to the Bookmark Toolbar folder for use and easy access while using Firefox 3.

Finishing Up
Now click the Close button after you are finished moving your bookmarks around to where you want them. This will take you back to the Firefox screen and you will have all your bookmarks easily accessible.