Domain Mapping Set Up

I am setting up a network site and will be using the Domain Mapping tool to allow people to use their own domain.
What I plan to do is post instructions on my site to show people how to set this up and offer it as an alternative premium service if they do not want to.
I have looked through the docs for this but that appears to be aimed at the host, not at a site user.
Is there any docs I can use to post step by step instructions suitable for a site user?
Thank you
David