Shower/ Bathroom Mold on Ceiling and Wall

I just need clear help/guidance. Recently moved into and this mold has been on the ceiling, in an a trailer with no ventilation or windows in this bathroom. I know a dehumidifier can help prevention, and I’ve read hydrogen peroxide will kill the mold. I’m nervous about it being on the ceiling for the proper PPE and every other surface in the bathroom. The yellow marks I had used the works to clean and left it alone because it made a chemical mixture I’m still not sure of but had gotten dizzy / sick. Additionally the wall is torn up and disgusting and I don’t know how to resolve that at all, looking for advice, don’t have much family to learn from or help and I’m lost. Trying to make this safe before my baby is born/home.