Only these three steps are essential.
Username and password are cs6210 to start. You may need to enable Hardware Virtualization to run the image in VirtualBox. Check out this Piazza thread for context, and this Wikipedia article for background.
You may find it convenient to customize your image in other ways — e.g. setting up a shared folder with your host OS. Consult the VirtualBox User's Manual.
You may also want to create your own image.