Hey Aaron. Welcome aboard!
You wouldn't typically need a servo unless you were building a Tri-copter. The servo would then articulate the rear motor for your "steering."
The only servo you'll deal with are the connectors, referred to as servo connectors (3 pin black end with 3 colored wires), which are used between the ESC and the FC, between the FC and the receiver, as well as other optional connections.
Hope this helps.