Zolko, thank you for the inspired work you are doing on the Assembly 4 workbench. My intuition tells me your approach will add huge functionality to this wonderful program.
I have read all 32 pages of comments and tried to work through the two tutorials you have given. Tutorial 1 was completed successfully. I'm still trying to figure out tutorial 2. As you can probably tell, I'm quite a rookie compared to most of the commentators. I found that with tutorial 1 I was able to follow the instructions of how but was having trouble with the logic of why.
In reviewing the Assembly 4 documentation, I came across: "the principle of Assembly 4 is to match coordinate systems in the assembly and in the part" and I realized this was my problem. As Yogi Berra said: "In theory, theory and practice are the same. In practice, they are not." The point of confusion for me was the process of using the Mapmode window and my total lack of understanding of the choices presented and which to use for a specific outcome.
Perhaps a really dumbed down tutorial, say the assembly of a box with a base and top, with an explanation of why the placement of each LCS in relation to others.
I also really like your technique of a functional structure approach and would like to see how you would do this for the aforementioned suggested structure.
I know these are baby steps to you and most of your readers on this forum, but remember, something is easy if you know how to do it, but getting there, that's the rub.