I would monitor the traffic on what app store your app is being downloaded to pinpoint frequency of downloads from individual markets, turnover rates from users, and ratings and comments which would contain valuable information from your users. Determining what previously provoked users to your product, what works what doesn't which such a large user base you should be able to derive a bunch of user data to be able to derive a methodology to further study habits of users and pinpoint at least some of the commonalities of good vs bad for your app.
To start you of look into Google Analytics, Fireball, Flurry, they are pretty sold for analytics of small to medium size traffic. All in all whatever method you use please take to account the current privacy issues now in your collection of data to avoid any future complications.

It's the wrong question. You should ask yourself: How do I want them to behave? And how do they want themselves to behave?

You should use MixPanel SDK and configure it to understand user behavior. Also use deep linking from Branch.io for deep linking.

With any mobile or web application you want to do one main thing:

Understand a user's journey through the app over time.

If you want the most professional and enterprise level of analytic information, i'd recommend a service called AppSee.
https://www.appsee.com/

From the time a user logs into the app, to the actions they take, to retargeting and understanding their future behaviors, I can help you out further if you have any questions.

Regards,
Matt McCullough

First, work on three different mock-ups of your next-generation app, each of which is focusing on a different aspect of your initial ideas.

Establish a small-but-effective-enough tester group having similar aspects with your target user and conduct an emprical research through in-depth interviews in three stages:
1. Before they start using the new app
2. During their initial experience with the app and/or after some use
3. After they become an expert user of the app

It sounds a very traditional method, but it always works great if you are prepared well with your early mockups and questions during the in-depth interviews.

Second stage of the research is the analysis of the findings which brings you lots of original and innovative potential ideas waiting to be implemented on your next generation products :))

Please always remember to include your users in your development process to make it more custom-tailored to their needs.

Thanks!

veyis

Firebase (Google Analytics) will help you to start. It has a feature where you can see how the user moves through your mobile app.

This can be very valuable on how your users use your app. You can also set up events to track any particular events in the mobile app.

In one of our apps, I used Google Analytics then (Firebase now) and found we had lots of users going to a screen on our app, I added some monetization and this helped increase revenue 25% overnight.

Looking at this data can be very helpful in taking you to the next level.

Cheers,
Mukul

PS - If you want help looking at the data or more tips, call me