How to extract one icon from an icon grid .eps file (a pack of icons) using Adobe Illustrator

I have been trying to figure this out for the last hour, but have not been able to yet. I am pretty sure this is a very basic operation. Can anyone provide me the url to a basic tutorial or just the steps? I just need to extract one icon from the grid of icons (pack of icons) that I just purchased and save it as a .png file so I can customize it with Adobe Photoshop.