In 4 Simple Steps, I will show you how to use Firefox Fast & Private Browser.apk on your Phone once you are done downloading it..
You can do this by using any of our download mirrors listed here. Its 99% guaranteed to work.
Make sure that third party apps are currently enabled as an installation source. Go to your device settings like so: Settings -> Security -> and allow "Install from Unknown Sources".
Locate the Firefox Fast & Private Browser.apk file you just downloaded.
Click the file and it will start the normal installation process. Tap "Yes" when prompted for permissions. However, be sure to read all on-screen prompts.
Firefox Fast & Private Browser is now installed on your device. Enjoy!