Upon initial login to Windows server you should see Server Manager. If not then launch Server Manager and from the left hand navigation select:
File and Storage Services
The drive we want to use as our new Veeam Backup Repository
In the Volumes view click on Tasks and select New Volume.
This will start the new Volume Wizard. Under Server and Disk select your local server and the drive where this volume will be created. Click Next
For both the Size and Drive Letter selections you can simply click Next as we are leaving these as default.
When it comes the filesystem we will want to select ReFS for the File System and 64K for the Allocation unit size and then click Next. After you have reviewed the volume creation details click Create to provision the volume.
The drive is now ready to be used with Veeam.