Step 1 : Ensure that you have the latest Desktop Firefox installed on your computer. Firefox 3 users might have to install Firefox Sync on their computers before proceeding. Firefox 4 users need not worry about this step as Firefox 4 comes with inbuilt Firefox Sync.
Step 2 : Setup your sync account with your desktop Firefox, you will be given a username, password and a sync key from your desktop Firefox. Write it down.
Step 3 : Start Rocket HD from your IOS Device and tap on the More Icon which is situated at the extreme right of the Top Bar. Once the More Icon reveals the Extended Bottom Bar, Tap on Firefox Sync icon which the 2nd icon from the right to open it.
Step 4 : Tap on Sync Login from the Firefox Module to start up the Sync Process. Enter the username, password and the sync key which you have written down. Please make sure that all these credentials are written exactly how they were provided. Do note that username, password and the sync key are case sensitive.
Step 5 : If all goes well, then you must now be authorized and all your desktop Tabs, Bookmarks and History should be visible from the Firefox Sync Module of Rocket HD.