The Atlas switches come with a two-position switch controller (straight or curved route). 12 volts AC from the transformer (red-black wires) is applied to the controller. Three wires run from the controller to three terminals on the switch. The switch itself is like any other piece of track and gets track voltage through the center rail that powers the locomotive. You're getting ahead of yourself. Buy whatever switches your track plan requires and read the wiring instructions and diagram. If you have a question, ask it on the Forum and you will get help.
MELGAR