Thanks a lot, Andras. Yes, I think you gave me a very good advice. I believe my post was consequence of getting nervous because the VTK books contents were not “Chapter 1 - The Mesh”, “Chapter 2 - Mesh transformation and operations”, “Chapter 3 - Rendering the Mesh” 
But now, more calmed, I began to find examples closer to my needs around page 105 in the User’s Guide. And, just like you said, by looking at examples I think I’ll be understanding things better.
My needs obviously come from a different starting point than VTK´s. It could be argued that I should look at rendering engines instead (like OSG, OGRE, or Godot), but I’m working in FEM research, and I need to visualize FEM results, so VTK is going to be the right choice (not to mention the better compatibility with other FEM tools if I use VTK).
My challenge now is to be preparing an skeleton app ready for the type of models I’ll be working with, and gluing my FEM code to directly access the VTK geometry. I wish to include animated models from the beginning, with skinning and morphing, because I’m going to apply FEM in animated situations, so I’d better have it ready from the beginning.
Yes, if I face questions I’ll ask them here. Thanks!