You didn’t give enough information to make a good start here. Exchange requires active directory. Do you have a domain with at least two domain controllers? I presume you want to use email with the internet. How is DNS set up in your environment? How many users do you have? If you only have 6 users then the easiest way to provide email would be with hotmail, gmail, your local ISP, etc. I suspect exchange is much bigger and more involved than your environment requires.