I'm still a relative noob to DnD and am playing 5e. We will be starting the Curse of Strahd on March 16 and I would like to be planning out my character. I'm having some trouble figuring out where to get information on races/classes outside of the player's handbook. Where else should I look to find listings/descriptions/rules/etc. relating to the races/classes that I can play legally in Adventurer's league?
The sort of case that brings on this question would be this.
"Choose a race. This season, you can use any race from the rules listed above, except for aarakocra.". I've never heard of this particular race. I found it in the monster manual, but I don't understand how that allows you to build a PC. That's why I'm curious about where all I can source my build from.