VMware disk files, or VMDK files, contain the contents of an entire virtual hard drive that runs within the VMware environment. These files typically contain entire operating systems within them, and are run through the VMware manager.
Create a new virtual machine for your version of VMware. There are many different types of VMware platforms, including ESX Server, Workstation and Viewer. Each of these contains different methods, so consult your version's manual for details.
Choose a custom set-up when prompted, and specify the amount of memory you'd like to assign to the virtual machine.
Select "Browse" when prompted to install a virtual disk. Browse to the location of your VMDK file, then double-click it to select it.
Power on your virtual machine within VMware. The VMDK file will automatically load as the device's virtual hard disk.