This is the first product from VMware where beta is free for sign up. Do not miss this if you are a interested with the next release of vSphere.
To sign up, head on here.
By participating in the beta program, as always you need to be able to install this in some environment. This can be your home lab or an isolated environment at your work place. It can also be nested however if any issues resulted from nested will limit the support you reeive.
So help sign up in this beta program and provide all your feedback and issues you encounter so that vSphere can remains as resilient, reliable and stable. VMware will need any inputs possible to better this release so do not hesitate to provide.
You will find all the documents and guides from the landing page upon signing up completion.