Terminal 3 is newly updated and will house the airlines from terminal 2 eventually, along with Delta, Hawaiian, Sun Country, Frontier, and JetBlue Airways.
On level 1 you will find baggage and ticketing. Once you have your boarding pass, head up the escalators to level 2, which will take you through security. Don’t bother trying to find level 3, you won’t find it, since it no longer exists.
Take the escalators to level 4 where you will find the gates, dinning options, and retail shops. This level will also give you access to the Phoenix Sky Train, that can take you to terminal 4, the east economy parking lot, or to the metro rail.
A few good places for food to try is Shake Shack (South Concourse), SanTan Brewing Company (South Concourse), The Parlor (Post-security), or The Tavern (South Concourse).