First time at a gay sauna: Any tips or experiences with saunas in Frankfurt?

Hey everyone. My boyfriend (30M) and I (23M) are traveling to Germany in a few months and we want to visit a gay sauna for the very first time.

​Since we've never been to one before, we have a lot of questions about how they work, the general etiquette, and what to expect from the whole experience. We’ve decided we want to check one out while we are in Frankfurt.

​Does anyone have any experience or specific recommendations for the saunas in Frankfurt? Any beginner tips would be hugely appreciated. Thanks in advance!