This video covers Packed Primitives in Houdini 13 and their usage in Instancing. This video is a more detailed explanation of a topic that is covered in brief in the Floating Islands training series.
Packed Primitives are a new form of geometry type that was introduced in Houdini 13. You can think of them as proxies. This video covers the various ways in which you can create them and use them for large scale instancing.
The second part of this tutorial is now online. It covers certain topics that were mentioned in the comments section.
Also a small announcement. The second part of the Floating Islands training series is now available. The video also contains a small promo for the second part towards the end of the tutorial.