How Does Moving Into Private Rental Work?

I'm looking to move out of student accommodation and into a landlord-managed property, which means that bills are no longer going to be included in my rent for the first time, and I'm just wondering how that works exactly. I live in Scotland if that's important.

This is probably an exceedingly silly question, but how does one... ah, pay their bills, exactly? How much should I expect to be charged for energy and water if I live in a 2 bed flat with one other person (also a student)? Is it easy to switch energy providers? Are some providers more expensive than others? How does paying for water differ from paying for electricity, do I go to different places for both?

Also, I've noticed some properties ask for references when applying. How likely is it that I'll be able to move in somewhere without one? Is that necessary or is it a courtesy? Thanks guys!