How can I install an app on an off-network device?

A

AC Question

I kept my Razr Maxx and would like to use it for some filming. I want to install a particular camera app to use with it. I have purchased and installed this app on my active phone (Moto X). I can't connect to Google Play with the off-network phone since it's not authorized for data access. Can I copy the app via microSD and install it that way? Does that require "rooting" the phone (if so, please point me to a helpful how-to on that)? Any other ways to do it?

Thanks!