how to do the addition gigs?

I was able to add small rooms in two of my gigs, one on the ground floor, and the other on the existing second floor. The issue I had was the budget, after adding a tiny room (closet?), and adjusting the roof, there was no money to decorate. I wasn’t able to “show” the client anything, because I was only able to add flooring and wallpaper without going over budget. The challenge I had was you can’t remove items in the house, so I had to find empty space for a doorway. Another issue was it won’t let you drag/expand walls, I had to use the room tool from the side of the house pulling outward, otherwise you get a message saying you can’t change walls in the house (or something like that). It was really difficult and I don’t think it’s working as intended.