Can the Extreme Danger attic and basement be used with the base game boards, and where do the stairs go?

Question

Accepted Answer

Yes. The designer confirms they work with the original two boards, and the stairs can go in an unlikely spot on those boards. Pick a sensible stair spot; lining up the basement and ground floor makes floor damage easier.

Flash Point: Fire Rescue

Can the Extreme Danger attic and basement be used with the base game boards, and where do the stairs go?