If you need to setup a windows server in a hurry you can download the evaluation ISO from Microsoft, here:
You can then at a later date convert to a fully licensed (retail/OEM) version of windows by running the following command from an elevated prompt:
Standard edition: DISM /online /Set-Edition:ServerStandard /ProductKey:YOUR-PRODUCT-KEY-HERE /AcceptEula
Datacenter edition: DISM /online /Set-Edition:ServerDatacenter /ProductKey:YOUR-PRODUCT-KEY-HERE /AcceptEula
You will need to restart.
One caveat is that you can’t do this on a domain controller.