Fred,

Here is part 1
Here is part 2

I have taken the liberty to adapt your files a bit in order to explain a few things.

When you draw a multi-level building it is very important that you work with exact X,Y coordinates. Hand-drawn walls will never stack properly and result in ragged walls, corners, etc. The most important change I made is change all coordinates in such a way that the ground floor and first floor have the exact same X,Y coordinates for walls, floors, etc.

This also makes it much easier to place furniture in a correct manner; in this case, e.g., with logical distances between two rows of restaurant tables.

Just have a look and compare what I did with your own design.

Hans