There is also a WIKI with very useful information so make sure to check it out.
Some basic concepts:
The World of Telara
The land faces an unprecedented challenge as dimensional rifts threaten the integrity of the realm. The Ascended (players) are heroes brought across time to help free Telara from the Blood Storm (A coalition of Gods from other planes). The players will encounter both local and foreign forces that are with and against them, and engage in massive battles for survival and power.
Full Details on racial attributes can be found here
The player must chose to be a Guardian or a Defiant. The Guardians are the chosen champions of the Vigil (Telara’s Gods) and will fight on their command. The Defiants will fight to protect Telara but blame the Gods for the Rift war. Both factions can coexist in guilds but have different starting zones. Please note Asylum has a vast majority of Guardians in guild!
The Souls / Classes
This game has a fantastic leveling system that allows you to customize your class and role in a completely new way.
Here are some tips about the settings
The chat window
Action Bars and Other UI