Typically most standard designs have the flat plasterboard ceilings combined due to being located beneath the same metal or tiled roof space. Uncombining one or more ceilings allows 2 or more different roof types to be selected.
The floor plan shows a balcony located above a the ground floor kitchen. This means this section of roof needs to have a different roof type modelled.
To change the roof type you need to unselect the zone requiring the different construction roof type. The attached example shows the Kit/Living/Dining (KLD) zone has been uncombined. The modelling shows that all other zones to this level have plasterboard ceilings insulated with R4.0 bulk insulation located beneath a metal roof with Anticon installed = all remaining zones remain combined.
Now that the KLD is uncombined, amend the KLD roof construction type to select the different roof type. The modelling shows the KLD zone still has a plasterboard ceiling insulated with R4.0 bulk insulation but is now located beneath a weatherproofing membrane roof.
If you do not uncombine the zone/s correctly you may accidently apply the new roof type to incorrectly zones. Always check your building summary to ensure the changes have made the correct amendments to the building envelope specifications.