This make no sense. Can you visit https://play.google.com on your desktop and search for Firefox there? You should be able to install it to your phone from the desktop site.

Latindude said

When installing Firefox to my Android version 4.1.2, from my desktop, by clicking on the link sent to my phone, from Firefox, I'm sent to the Optimum sign in page; the problem is I no longer have Optimum service, I have Verizon Fios triple play, How than do I complete this installation of Firefox, to my phone and why was I directed to the Optimum sign in page? Please advise me what I need to do; Thanks!

Thank you so much, kbrosnan, your solution worked! Have no idea why, after clicking Firefox's link to sync to my Android phone, I would be directed to Optimum, but what counts is your correct solution! Thanks again!