There are two operations left to do.

1) Subtract the cafes from the canyon solid because you can't have overlapping solids.  Click on the Combine tool, click on the canyon as the Target and click on a cafe, then click on the same cafe again. This second click is to remove the cafe solid that was cut from the canyon. It is called solid in the structure.  Click on the Select tool so you can repeat that with the other cafe.  There may be a way to keep going, but I haven't looked for it.

Now you have a canyon with the cafes subtracted from it and two cafes.

2) Turn on Share Topology.  Click on the Design tab, click on the canopy-v2 file name, click on Properties and on the line called Share Topology, change it to Share.

Now there are three solids that share common faces.

Here are the three named selections of faces for the cafe on the negative x side with the cafe-air solid hidden.


Mesh below is deliberately coarse just to show the separate solids of air under the canopy.