In UMC, click File Access Protocols > NCP.
Click the Search icon and specify the server name.
or
Click Browse and select Server Type to list their associated servers. Select the required servers from the list, and then click APPLY.
Select the volume, click More Options icon, and then select Add secondary volume.
You can add one secondary volume to a primary volume. On selecting multiple volumes, this option is disabled.
In Add secondary volume, select the secondary volume, and then click Confirm.
This adds the selected secondary volume to the primary volume on the server.