Installing multisite on Wordpress with a Mac

Ok...I've read through the manuals, and I've been working with this off and on for a month but I cannot figure out how to install your multisite plug in on wordpress. I am using Host Gator as my hosting. Is there someone I can talk to to walk me through this? Or a fee I could pay to just have it done? If not, is it possible to cancel my order because I just cannot figure this out. Thank you so much!