So i dont have this core book yet and was wondering what the starting resource is? I know Duty is a reward you can give that can be spent to earn extra things from the Rebellion. Whats their starting resource options?

Stolen Lambda, some Y-Wings or a Base.

Duty isn't spent in itself. When the group has enough they gain a rank with their organization (which is the Rebel Alliance by default, but you can make the system work with others), and that gives them a perk (usually but not always gear or vehicles) based on their new rank.