1. First you go to the virtual machine menu then select details
2. Next select the Hard Disk menu and edit
3. Resize disk
4. Go to VM and check the current condition (openconsole or rdp)
6. go to disk management
7. Expand disk with disk available or create new disk
*If you want to expand then right click on system c and click extend
*If you want a new partition, right-click on unallocated and select new simple volume.
here is an example after expanding / extending the disc :
