Ceiling/walls - what order?

[Draughtsman]

As part of an extension I'm converting a car port to a room, the old car port has another room above it.

Would I plasterboard (insulated type for heat retention/sound proofing)) the ceiling before I do the walls?

Do the recessed edges that take the joint tape/mesh run parallel to the ceiling joists or do I arrange it to minimize the amount of taped joints that won't have recessed edges?

Thank y'all kindly
Dain

 

[Bonni]

Plasterboard ceilings first and across the joists.