Hyper-v in my own words for people to understand is quite simple. It is a virtualised platform that uses a very powerful server to create mini servers within which leverages resources from the powerful server which in IT terms is reffered to as a host.
The vm's you create should coincide with the number of proccesors and RAM the host has and we should becareful to not over utilise.
Hyper V is a role of Server 2012 that needs be installed prior to any of this that needs to be setup.
If you are wondering about disk then that also is used from the host if there are no SAN's that are used in the setup.
The picture above gives a perfect indication of how this works.
Thank you for reading.
Regards,
@trev03