Hi and thanks,
did you have a look at the SampleBrowser - it has a source code tab for all samples, maybe that can get you a good start. We're working on getting more screencasts, samples and documentation up and running, just trying to balance getting functionality, fixing
bugs and documentation. Kinda hard, but we'll get there.
As for your request for concept mapping :
1. Balders Game is more like the Viewport3D - basically just a rendering surface for Balder to use. It has the concept of a Scene within it, which used from Xaml is the default place for items added directly to it.
2. Balder has Mesh, but you can't define it with Xaml like in WPF - you should look at
this tutorial for more details
3. Geometries / Meshes has a Material property - you can assign it through Xaml. I recommend you looking at the SampleBrowser and the Material editor sample. It shows the properties you can assign to a Material for now.
The plan is to create the SampleBrowser for all targets that Balder supports, just need to clean up some of the code in the SampleBrowser so it can be reused - don't want to recreate all the samples for all targets.
Hope this helps you a little bit on the way and hope you enjoy Balder!