How to learn MetaXR Spatial Anchors for Unity

Hello!
I cannot seem to follow the documentation for MetaXR Spatial Anchors - they implemented 'Building Blocks' and I cannot find any documentation for it, I am working on a simple singleplayer local spatial anchor setup and I simply cannot make any headway. How do I learn to use this feature? Its so important for Mixed Reality 😞

Also - if you happen to know the most stable version of Unity and MetaXR (or if you use other XR integrations) that offer DepthAPI Dynamic Occlusion/Room meshes/Floor pathing for NPC's, otherwise I've been struggling on Unity 2022.3.24f1 with MetaXR v63