Thank you The rocky ground is based on following Wes's tutorial actually. I've actually pretty much only watched the tutorial series he's put on the Allegorithmic YouTube channel.
The series they have for Substance in Unity 5 was really really good (especially if you do game design because it opened my eyes to a lot of the features for making material settings available in the game engine), the rocky ground one was really good as well as an overview of PBR and the toolset. I guess it helped me pick up the workflow quicker that I've been using Blender for a few years now and Cycles is a mostly node-based material system, so I'm used to node based workflows.
I tend to learn by trial-and-error, brute forcing my way through, and googling when I want to find out what a specific tool I come across does. Probably not the best way to learn since it means I'm really inefficient to start with, with lots of "Ah-ha!" moments when I find out something new the software can do or a new technique, but I personally prefer learning at my own pace like that.
Ninja Edit: This is one of the first tutorials I followed for Substance Painter, it was actually really good in showing off things like the mask tools and bakers... not the best tutorial or audio quality, but I found it enlightening.