The SketchUp API documentation is a concise dictionary of the API’s modules, classes and their methods. It is not a teaching tool and the snippets that are shown are mostly taken out of context and often not that helpful.
Contrast this with the SketchUp C API which have no snippets at all.
Trimble and it’s SketchUp division are not really in the programming education business. It is not their responsibility to teach basic programming concepts. The web has free and paid tutorials on this available. Or a person can take a night course at their local junior college.
The same holds for Ruby. The SketchUp API simply extends core Ruby and a coder needs to learn Ruby first. If they don’t, then the SketchUp API documentation looks to them like a foreign language.
This should be done somewhere after your step 2 and before step 4. I know that enthusiasts usually don’t formally attempt to learn Ruby during 1 or 2.
There are many free resources to learn Ruby and Trimble need not reinvent the wheel here: