Step 1 | Download bittube_airtime_donations_adblocker_wallet-2.0.0.4a-fx.xpi

Step 2 | Open right sidebarmenu and click on Preference

Step 3 | Click on Extensions & Themes at the left sidemenu

Step 4/A | Click on configuration icon and Install Add-on From File

Step 4/B | Drag and drop the downloaded file

Step 5 | Click on add