[Blind-sysadmins] activation windows server

Hi. Tried a couple of commands and did try activating windows server 2019 essentials 64 bit inside hyper v and a remote connection. Tried googling and either did not work inside command prompt or windows power shell. So how do I activate it short of having to do a recovery. Using hyper v manager latest windows 10 64 bit pro 2004. Thinkin use the data centre, but not sure. When I do a win ver. It does not seem to tell me which version. Thanks.