My notes are based on installing the Windows Server Evaluation version.
Download the EVAL Windows Server ISO from here and the VirtIO Drivers for Windows from here.
Upload the ISOs to PVE.
Create a new VM in PVE.
The configuration here that makes a difference for a Windows OS are the following:
Now that the VM is created, add a second CD/DVD Drive then mount the Windows Server and VirtIO ISOs.
Start the VM, you should boot into the Windows Server installer.
Walk through the installer as normal. When on the drive selection page, select the option to install a driver.
Open the VirtIO mount and select the appropriate hardware and Windows version.