Having a proper metric system in place is essential to build a product without wasting money and time.
Read about the cohorts to understand how they work.
Look on the internet for more information.
Define what type of metrics will validate your hypothesis.
Define what value you expect to have.
Establish the baseline.
Build the first version of your product and measure the value of the metrics.
Tune the engine.
Improve your product in order to get the numbers you defined at the beginning.
Make the decision.
Keep the product and develop it further, or pivot.