When you’re setting up your Subscription settings for your app on Google Play Console, there’s a form you’re going to fill. Here are some quick answers for you to cheat from:
Enable authentication: Off / uncheck thebox
Message retention duration: This one’s up to you, whenever you think you may want to go back and check things. The app has nothing to do with this setting.
Retain acknowledged message: Off / uncheck thebox
Expiration period: Has to be Never Expire.
Acknowledgement deadline: 10 sec is more than enough for us, you can leave it as is.
Everything else, you can leave as default.
And feel free to ask us if you have any other questions.