Blizzard posts a New Player's Starter Guide for WoW Forever
Blizzard's official starter guide walks through account setup, the first-login Experience Preset (Classic or Enhanced, both adjustable later in Options), and picking a Ruleset before making a character. Normal, PvP, Roleplay and Roleplay-PvP are available at launch, with Hardcore coming later. Grouping, guilds, dungeons and raids only work with players on the same Ruleset and faction, so agree on both with friends first.
Source: Blizzard Entertainment, worldofwarcraft.blizzard.com