Design test plans & evaluate results for an A/B test

My app aims at switching from monetizing with an ad only, to finding optimal revenue mechanisms between 03 models: ads, in-app purchases, and subscription. I want to increase its LTV at the same time by improving engagement metrics. I want to use the A/B test to validate & find valuable learnings for the new mechanisms. Do you have any ideas on how will I design test plans & evaluate results?

Background research, defining hypotheses, calculating test period, test variants, test populations, evaluate the test results.