Architecture techniques. File included

Support Modeling
1

Here is how I am trying to make buildings by creating a plane and duplicating it here is the file and what do all these signs mean. File below. I want to know if this is the best way and how I can improve this way.

Attachments

Architecture.blend (368 KB)

2

I am using a connect the dots type see in this file I connected all of them. Now i Will extrude them. What do all the the other symbols mean.

Attachments

Architecture.blend (394 KB)

3

What do all the signs mean?