You can download it here.
Also check out the documentation here, the first doc that I always go to is the Configuration Maximums to see how things have grown.
And be sure to read through my Summary of What’s New in vSphere 6.5 post and What’s New in VSAN 6.5 post and also check out my huge vSphere 6.5 Link-O-Rama which is your one source for all vSphere 6.5 related links on the internet.