Tips for using air purifier in small room with a bathroom and how to avoid mold

I just purchased a levoit core 300p for my small room in which there's a bathroom. I shower every night and whenever I do, some warm shower steam always inevitably leaks into my room. I open the windows (which are quite small) but eventually the steam does clear. What is the propper etiquete to follow with the air purifier? Some sources say to turn it off while showering, others say to actually keep it on and to turn up the air strength so that no humidity gets trapped. I'm confused and don't know what to do. Any tips?