New Blog Template on WP Multiuser Site

I am a first time blogger, with no site active yet. New to Wordpress and WPMU. Looking to set up one website (i.e. for Painters), and then copy EVERYTHING (themes, plugins, widgets, API's etc etc) to a place where I can use it for other websites, (i.e. plumbers, carpenters, roofers etc)

Have a dedicated server with cPanel.... don't know what to do next. I'm leery of getting in and messing around with file structures without your guidance.

Thanks,

Bob Baumann