Is their downloadable files for the completed version of the 5 tutorials?
There used to be a zip download at the end of each stage but looks like that has been removed when the new docs launched. Work through the examples and you will hopefully get a better grasp of things. All the file paths should be included above code snippets to make it easier.
If you're on the look out for more examples you can download the examples from the book - https://github.com/chillu/silverstripe-book
If anyone has time to package up each tutorial as a download please get in touch and I'll update the docs site.