MA 3D is an expansion for grandMA2 console, not stand alone visualiser.
MA 3D has no "fixture library" - what you see in assets are just models, empty "shells", which are optionally.
MA 3D joins with show from grandMA2 and renders/visualises show from that console. Lights visualised in MA 3D are defined within grandMA2 show itself.
You don't design a set like in WYSIWYG, and then connect console. You connect console/onPC with 3D and patch/position fixtures (optionally add objects to envirnoment)
I don't know where you searched, but help.malighting.com holds pretty much everything you might need, including MA 3D manual. It was quite enough for me.