(The VL image will automatically install as a KMS client looking for a KMS server on the network to activate. This is the easiest and quickest for corporations who already have built the KMS infrastructure.
The retail image will require entering a key before installing. You can use it as a KMS client by providing the appropriate key.
For either one, you can use KMS client, MAK, retail or OEM keys - retail image before install, and either of them after.)