Step 1. First off, you need to download Firefox Web Browser app from the AppStore.. Step 2. Open the Facebook app and Tap Share on any video on your feed or timeline, then Tap Copy Link.. Step 3. Go to slicelive.com, and Paste the Video Link before tapping Download.. Step 4. Tap and Hold on any video format available (HD or SD). Then Tap Download Link and confirm the download. This coupled with an online Facebook downloader will allow you to download any videos from Facebook and save it to your iPhone. The method is quite simple and allows you to download Facebook videos in a matter of minutes. In this guide, we’ll show you how this can be done.