Briefing room is for weather, planning minima, NOTAMS, brief the cabin crew, if there are limitations on cross winds etc maybe decide who will operate which flights, and fuel planning.
Departure and arrival brief should be interactive and relevant. If it's someone who haven't flown with before, or not in a while, probably a full brief on ground emergencies and vital actions for evacuation, then any emergency turn should an engine fail after V1.
Then into how you will actually fly the departure, relevant nav aids and track, how you plan to use the autopilot, and specific threats to the day (complicated SID, low QNH increasing risk of level bust, high terrain, lots of birds) although it is pointless briefing a threat unless you are also briefing something you plan to do to manage/mitigate the threat.