What is the correct procedure to install apps from Google Play store?

I have seen lot of threads with the same topic from multiple users (I’m a paid user) and there seems to be no definite correct documentation or procedure on how to login and use the Google Play Store on real device manual testing.

I want some support to actual demonstrate how to do it, since I have been breaking my head for 5 hours now with the so called “documentation” here → How to Test Apps Installed via Play Store? | LambdaTest which is technically doesn’t elaborate much on the login procedure.

I have been unable to login into Google Play on Real Devices. I would challenge any support team, they can have full access of my account and demonstrate how to do login into Google Play Store and install apps from there.

There is already a “work” google account pre-authenticated which is acting as a big blocker and interrupting the normal authentication of the app with my personal Google Play credentials.