All the official documents related to vSphere 5.1 can be found in the below link
http://pubs.vmware.com/vsphere-51/index.jsp
You could find some videos relate to vSphere 5.1 http://vmwarelearning.com/
Before you start you have to make sure the hardware is present VMware HCL and its supported
I have Esxi running on one of my servers but I guess my new licensing gives me an enhancemen
You can check the feature which are avilable for Essential Plus license here
Inorder to use the advance feature like HA, vMotion you would need a shared storage like iSCSI, DC or NFS