(Almost) every section in this documentation begins with a practical guide (in this font color). This is a short section with a few typical examples, which - by intuition - make it possible to figure out how to do the most usual tasks, without having to browse the whole section with more details.
The second part of the sections is a more detailed explanation of the given class or topic. Reading this part should be enough to understand the usage of everything.
The third part gives you details of the implementation, and such details, which are usually not needed in the daily work. Skip this part, unless you want to figure out how blop works in the background, you want to discover the solution for a bug, you want to write some extensions, etc. Also, this section gives links to the source files.