java – Android Eye Exercise Application

I am currently working on an Android application for the moment, I am new enough to do so and would like to have some advice on some things.

The application I create is based on eye exercises, it allows users to exercise their eyes by following something on the screen, such as a point, for example. I need to implement a timer or something else with which I can save the time so that the time of use of the application can be saved in a database. data (Firebase), then the data could be displayed on the graph.

I would be happy to receive ideas on the best approach to adopt or a tutorial to your knowledge.

Thank you