Mozilla website info says that Firefox android is comparable with Nexus 7. But when I attempt to down load I am directed to the Google Play Store where the site informs me that my devise is not comparable and I am unable to download. I tried to go to Mozilla apps and the site directed me to download Firefox Beta. When I tried to download I was again directed to the Play store and the site said incompatible and was unable to down load. My tablet is checked for downloads other than Play Store. How do I download to this devise?