Qt3D. How to add node to the scene on mouse click?

[jura]

Hi guys!
I'm trying qt3d - unfortunately there is no docs on it (autogenerated docs are useless, but if I've skipped something else - please tell me).
So, I took some c++ sample, and modify it. As I understood I can add anything in scene init and that addition will affect scene. But if I add something like:

Qt3D::QEntity *entity = new Qt3D::QEntity(m_root);
entity->addComponent(mesh);

Then it won't show in scene. So, maybe I need to call something 'hey refresh scenegraph!'. Can you tell me something about that?