Whew, this editor is kickin' my arse right now, but at the same time I can see how you can really start sailing by once you figure everything out and get things kinda working how you want it to. There's certainly an accessibility price to pay for all the customization this editor allows for. Too early to judge though just…
I made a tutorial on modular pieces in my artsation challenge tutorial series, it would probably be applicable to building fantasy environments :) https://youtu.be/xC0uL_QQWeY
Found a tutorial which explains how to do that with xnormal aswell. http://www.donaldphan.com/tutorials/xnormal/xnormal_occ.html a bit scrolling and your there. nice for highlights it seems.
search for pixel art tutorials. The hand painted tutorial torch referenced is good too - the same fundamentals apply you're just working at a smaller resolution.
bumping because I also am following this tutorial and having similar problems. Up to date tutorials for making hair for games are woefully hard to come by!
Below u can see my result of the great Mech Tutorial by Tim Bergholz / chamferzone. I really enjoyed that great tutorial and can absolutely recommend it.