The first step to create a virtual machine is to click on the New button in the top left hand corner of the VirtualBox Manager window. This starts the New Virtual Machine Wizard which will walk you through the steps required to get a new virtual machine up:
Next, enter the name of the virtual machine. What you call it is entirely up to you. VirtualBox will try to figure out what OS version you plan to run on the VM based on what you name it. If the name of the VM has Win 7 in it somewhere it assumes that you will be installing Windows 7 and will adjust itself accordingly:
Next, you’ll be asked to select the amount of RAM that you want to allocate to the virtual machine:
Next, you must specify a virtual hard disk for your VM.
There are multiple ways in which VirtualBox can provide hard disk space to a VM, but the most common way is to use a large image file on your real hard disk, whose contents VirtualBox presents to your VM as if it were a complete hard disk. This file represents an entire hard disk then, so you can even copy it to another host and use it with another VirtualBox installation:
Select VDI hard drive type and click Next:
In this example we will be using dynamic disks, but fixed disks will work just as well:
Next, type the name of the new virtual hard drive file or select a different folder to create the file in and click Create:
That’s it. Now we need to install the guest OS.