Replace the ceiling

[Kenneth Nilsson4]

Hello,
First, many thanks for the invitation!
I am going to replace the suspended ceiling with recessed spots to a regular one, quite simply.
How do I do it right?
Do I install a vapor barrier and then battens to attach the ceiling to?
Should one use "double" studs (for an air gap)?
I think I've seen both options. Which is best then?
Many thanks for the advice!

 

[Demmpa]

When was the house built?

What is above the roof?

Exactly how is the roof constructed today?
From above the insulation to the ceiling.

 

[Kenneth Nilsson4]

When was the house built?

What is over the roof?

Exactly how is the roof constructed today?
From the top side of the insulation to the underside.

Hi,
The house was built in 1964 with a flat roof. Reinforced asphalt felt on the exterior and self-supporting trusses with insulation. Standard tongue and groove wood towards the ceiling, then there were battens and the "paper ceiling" was attached to them. When we lowered the ceiling earlier, there was a foil between the battens and the ceiling which the carpenter removed when he set up a new framework for the new lowered ceiling with recessed spotlights (in metal cups, 13 cm deep). So the question is, should I put up new foil before the new battens that I will then attach the ceiling to? How should I think about this?
Thank you very much for the answer.