I managed to get a simple blocky thing up and running. Finally managed to load a texture for a material without running into errors. It took a lot of trial and error, and had to go back and forth with the example capx's until it finally worked. My current opinion is that there is a bit of work to do with making the plugin more accessible, and as others have said, it would greatly benefit from some documentation to clear things up. Obviously stuff like that takes time, and I'm happy to have something to play with until then. Still trying to figure out how to load a sprite, and the particulars of creating and applying materials to objects. It isn't exactly user friendly at the moment.
Does anyone know of any good resources for learning the basics of relevant 3D game concepts? I've googled around, and there are lots of bloated tutorials that either focus too much on a particular engine or language (which obviously doesn't help with Construct) or just assume too much understanding at the beginning. Things that should be simple seem quite a chore, like, you have to load a texture file into Construct first, and then also load in the event sheet, and then create a material and reference the loaded file, and then create a piece of geometry, and apply the material. It's like 4 or 5 steps that could (should?) be taken care of behind the scenes. It's not like you'll ever apply a material without first loading the texture, right? I mean, Construct is generally very good at hiding the unnecessary complexity from the user. It's what makes Construct so awesome. If you've imported an image file into the project, I think it should be taken as granted that you'll be wanting to load it before you use it.
Anyway, take this as a comment rather than a complaint. It's not like I'm unhappy with the purchase. It's just that this plugin has so much potential to completely transform Construct, and I hope it gets there.