It is understood that Yocto is a system for building a system image and associated test tools such as a virtualization environment. Since the entire Yocto infrastructure is complex and powerful, it is similarly difficult to understand.  It is this infrastructure usage which must be documented, in the form of a basic tutorial.

I think a set of steps detailing how to build a single application (e.g. an element of the target tool chain, such as g++, or ld), not an entire OS image, would be a better introduction to the framework provided by Yocto, even if that is not the intended usage.  These steps should include explanations of the directory structure, the (too) numerous configuration files, and more.


A user of the tutorial would be instructed to download the core Yocto environment, not the entire poky reference build tree.  Then they would add in a single component as mentioned above, configure the build for a target architecture and OS, and perhaps set some additional interesting options (perhaps packaging, or testing, or something).  Then they would launch the build, and observe the behavior.  Finally, they could inspect the output of the build.

Working up from this to an entire target OS image with supporting virtualization engine, etc, is really fairly straightforward, and little more than a mental exercise, but the basic steps are much more fundamental to understanding how Yocto is put together.