For client machines to find your KMS host automatically, you must publish the KMS SRV record in DNS.
After the OS is installed, open (or PowerShell). windows server 2019 kms iso link
There are two primary ways to obtain the official installation media: For client machines to find your KMS host
DISM /online /Set-Edition:ServerStandard /ProductKey:N69G4-B89J2-4G8F4-WWYCC-J464C /AcceptEula windows server 2019 kms iso link