I'm more interested in adding stuff like .NET, VC runtimes, Flash, or updating DX.
Yep, but this is the common approach that historically does not work (mind you, it may work for you , but it would be an exception), curiously enough simple things are simple and complex things are complex.
There are introductory tutorials because there are about simple things that can be learned through a tutorial, and there are not "advanced" tutorials because by the time you would be capable of following an advanced tutorial you would need not the advanced info in the form of tutorial.
And more generally you are at a junction.
You have to decide if you are a "passive" user of the Winbuilder (in which case you simply get the latest project made by a Developer and run it / use it to build a PE or whatever choosing among the choices the Author or Maintainer of the project gives you) or you try to become an "active" one, capable of creating your own .scripts or modify the existing ones to better suite your needs.
If the first, you have no chance, if something is not already in a project, but to specifically ask for (or beg for) it on one of the forums dedicated to Winbuilder, hoping that the project developer or another developer will make it for you, if the second, you will need to study, and study a lot.
You have a new tool in your hands, you need to get familiar with it playing with it and attempting to do simple things with it, and only once you will have had the time to understand how it works, which quirks (if any) it has etc. you may think of making an attempt to complex projects.
In any case, it remains a tool (and nothing more) the "rest" (which is actually the most complex part) comes from general and deep knowledge of the OS and of the other several tools needed to trace a program or a subsystem.
Imagine that you receive as a gift a new Porsche 911, and while you are an experienced driver of "common" cars you have no racing experience on track, the car handles just fine and it has some real horse power under the
bonnet boot , for using it safely you need some time driving it normally, getting the feeling of it without ever overdoing it, but while you are an experienced driver of "common" cars you have no driving experience with such a powerful car nor racing experience on track, if you want to go ahead you will need some advanced race driving courses and a lot of track laps before you can even think of taking part to a race, nothing that you can learn with a "tutorial" unfortunately.
The usual advice is to take an already existing "simple" project and play a lot with it, adding or removing .scripts, changing the settings, adding or adapting .scripts coming from other Projects, little by little you will get the hang of it, then, if you want to take the plunge and switch to "active user", you will need to start by reading a .script (for a "simple" program) and try to understand what it does and why the Author of the .script used a given Winbuilder .script syntax (instead of another one) to achieve something, then study Winbuilder Syntax and finally be able to write your own "simple" .scripts again for "simple" programs, this takes time and dedication, before being able to tackle any more complex chore.