Please see this article for a description of the different license types HERE

When adding servers/VMs - here are the options you choose (again, based on the licensing model linked above)

1) add a server

- use this option when adding a stand alone physical server

- also use this option when you have licensed hypervisors and plan to add a VM which resides on a licensed hypervisor.  the system will automatically assign a VM license in such a scenario (you must have licensed hypervisor licenses and must have appropriate VM licenses available)

- also use this option to add a openvz/virtuozzo master node

2) add a stand alone VM

- use this option when adding a VM on any hypervisor platform or common public cloud platforms

- Max RAM = 32GB per VM