You can use Firefox Sync to share your bookmarks, passwords, settings, history, and tabs between your desktop and mobile. First just set up Firefox Sync on your desktop and then add your mobile device with the easy setup code.
Enter the setup code on your desktop to connect your mobile to your Sync account
Do these steps on the mobile device that you are trying to add to Firefox Sync.
If you are trying to add a device to Firefox Sync and you are not near your computer so that you can enter the code, you can still get it done by entering your account information.
Do these steps in Firefox for mobile on your Android device.