To record via your phone, you need to do the following:
1. Buy premium in the app
3. Immediately after that, exit the broadcast (so that you would not be in the list of viewers twice).
3. Log in to the premium through the browser on your cell phone
4. Done! Now you can make a screen recording while in premium.
Many also use an application on a computer that mimics android. They download the app and just make a recording with any program on the computer