Recommended version: VMware Fusion / VMware Player 6 or newer
Obtain VMware Fusion or VMware Player.
Install it on the system you will use as the virtualization host.
Launch it on the virtualization host.
In the File menu, click Open... or Open a Virtual Machine.
Select your copy of the the Helion Stackato VM.
When prompted with the question "Did you move this virtual machine, or did you copy it?" select "I copied it".
Start the VM.