You also have to have a licensed copy of Windows that you can install on the Apple Computer (Within Parallels). You install parallels and windows, and it runs a "Windows Virtual Machine", which just means that it simulates a windows computer inside of the Apple IOS. You can then easily switch between the Apple IOS and Windows environments. It works pretty well, but there is some cost involved (Parallels and Windows). It also does take some of your computers resources (Memory and Hard Drive Space), since you are running two operating systems at the same time.
We have that there is a tool called "Boot Camp", but we don't have any experience with that particular tool. Based upon our research, Parallels seemed to be the most popular and it has worked well for us.