i think basic call center (Contact Center) comes with 2 agents and 1 skill set,
A skill set is the actual software device that allows calls to be Qued, On the bcm it is a keycode that enables this feature,,,within the skillset you define how long a call stays qued and what announcements the caller hears while waiting in Que.
2 agents is good because you can have a second person log into the skillset to help answer calls during peak times if you like.