Here you can see the simple steps to understand hbo max/tv sign in activate process in your devices.

First download the Hbo max app on your devices from the playstore or apple app store or microsoft app store.
Then open the app and select sign in account
Then select the sign in through the tv or mobile provider
Then select your provider from the shown list
And view all provider and select your tv providers
Then enter your username and password from the sign in account to begin the streaming process.