For this article I will be using VDI since it gives good performance and is easily to use.
The next option will allow you to select either a dynamic disk or a fixed disk. I normally use dynamic disks since I like to keep my vdi files small and try not to waste space the guest is not actively using and performance impact is minimal.
Next, we will be asked for how big of a drive to create and this step is important as it is a bit of a chore to increase a VDI file size. We are going to use 25 GB which should be enough for what I am doing, adjust though to fit your needs. The VDI will be kept in the same folder as your virtual machine configuration files which is by default in the My Documents folder.
This next screen is a summary of what is going to be done by the drive wizard and this is your chance to make sure everything is correct. As you can see, I have everything going to a separate partition vice the default. I find it easier to keep the virtual machines on a separate partition than system drive.
This last summary screen is just confirming you want to create the virtual machine with the settings you requested. After you click create your new virtual machine will be created and almost ready to start the installation