Need Help Setting Up Network and Question About Request

Hey guys, so, I’m an absolute newbie when it comes to working with WordPress, and I’m trying to set up a multisite network but don’t know the first thing about setting it up.. even have a couple developer friends who have been doing CSS for my site but don’t know anything about WP. If I could bother anyone here for help with this, it’d be greatly appreciated.
Another thing too, I was wondering if it’s possible to set up a system where I can post “universal posts” (posts that’d post on all 3 blogs I’m incorporating in the network) while still having unique posts for each of those 3 blogs. If anyone can contact me to talk further about this, my e-mail is mikeninety@gmail.com. Thanks.