Unless you only want users with a + or an @ next to their nicknames to be able to speak I wouldn’t set the room +m. What I think you want is to gain @’s (moderator/room operator) status to control your room. If so then you must idenfity to nickserv using:

/nickserv identify YourPasswordHere

then type:

/chanserv op

You should now have an @ next to your name and can control your room.