1) negatively pressure the room and seal from rest of house. Close off and seal hvac ducts to area
2) air scrubber for the room while working and adequate Ppe. An n95 or better respirator is fine, p100 or filtered air pack is better.
I use a hepa rated Miller p100.
Safety glasses minimum and gloves. Tyvek suits do the job, but suck to wear for demo.
3) remove, bag and discard affected Sheetrock and any other compromised building products.
4) stop moisture intrusion.
5) clean up mess, vacuum everything. Micro ban.
6) dry the room to below 17% wood moisture content. Reconnect hvac
7) reinstall Sheetrock and finish.
You can run airscrubber until project is done. Running a dehumidifier while painting will aid in dry times.
If that's a bathroom, make sure ceiling is insulated well, and there is a good exhaust fan to remove humid air during bathing. Make sure there is no outside air entry into room while running fan. Vent the fan completely to outside with a damper.
Make sure all ceiling and wall penetrations are sealed and insulated to not allow air to enter from attic back to bathroom.
I know chlorine products are effective for killing the mold, but I don't like them due to health concerns. I also don't like them bc of how caustic they are to everything else.
Mechanically remove what you can Sheetrock etc.
Hepa vac what you can't and wipe with cleaning wipe and treat with anti-microbial. You can use encapsulation products like "fosters".