Hello.
the essentials kit includes 6 VMware vSphere licenses for 3 hosts of 2 CPUs each and a vCenter Essentials Server license.
When you register your licenses with VMware you will have access to download the media, it is recommended to use your business email to register with VMware with your company details (if the licenses are from your company).
You can enter and assign the licenses online, no need to reinstall or reboot the computers.