Most of colleagues who are interested with VMware VSAN may know but I am saying for unknowing, VMware StorageHub portal is the best resources for VSAN, vSphere Storage. It is a perfect point of reference to understand what is VSAN, what/how to do, how to deploy, different use cases, design recommendations with the best practices and so on.
If you are in first steps and only you say “I heard it, but I do not know what it is”, you can watch short video series with expression of Elver Sena Sosa from Vmware VSAN channel. He describes the product as very easy and understandable in these videos.
Also you can find Technical information in VMware vSphere Document page, but if you see the refence architecture with best practices or you say “I need more details with use cases” pelase go to StorageHub. Links are below.
StorageHub : Link-StorageHub
VMware VSAN Technical Videos : Link-Youtube
VMware vSphere Docs : Link-WebDoc