Build access to deck/balcony using dormer or other means

[Evolution]

Still working on the Coastal res for the boss. He and wife want access onto what would be the floor of the attic and out through a dormer onto a small observation platform / deck. I dropped in a floating dormer, but I am not able to turn it into something like a roof top balcony with access via the dormer room. Since I added the dormer on the roof, it is (showing) on the attic level and I am not sure if I need to go down to the floor below which currently I do not have any walls placed. I built the attic using the tutorial for building a story and a half room. How would you model the "observation deck" and access?

   

COASTAL RESIDENCE FOR CECIL and HELEN WILLIAMS OPTION WITH DORMER DECK FOR CHIEF FORUM.zip