How to install the app:
Phone:
Use the Windows Device Portal to install this (There's an option to do it on your phone if you don't have a PC to help you): https://docs.microsoft.com/en-us/windows/uwp/debug-test-perf/device-portal-mobile)
PC: Add the certificate to the "trusted people store" then install the appxbundle. There are other methods too but this one is the quickest one as far as I know.