This is the second video in this series.
I am only touching the surface of the concepts.
The idea is that you know about it and when its time to learn it in more detail you can do so with the documentation and other more deep tutorials.
So in this series you only get an overview.
In houdini everything is sort of interconnected and will only make complete sense when you have more of the full picture.

But i iwll try to put attention to the stuff that confused me when learning houdini.

geometry „format“ data model

points
vertices
primitives
detail

edges:
some more stuff about edges
http://www.sidefx.com/docs/houdini/vex/halfedges

packed primitives
http://www.sidefx.com/docs/houdini/nodes/sop/pack.html