Second design on Sketchup with stairs

Here is my second design on Sketch up.. I am struggling a little bit still but slowly learning tricks! This design also includes my stairs going up and down into the studios from the 'exhibition space. I especially struggle with the internal parts of my designs, and making shapes fit doesn't seem to always work for me... 

This is based on the following drawing:

Above ground: Bestial

Below ground: Omen