Unreal Engine Cesium Tutorial "Using Custom Controllers"

In “Using Custom Controllers” tutorial in Unreal Engine I am having difficulty navigating
between the 3rd person actor and the vehicle and driving the vehicle. My blueprints are
correct but how to switch between actors and also drive the vehicle are beyond me. The instructor
assumes this is known but unfortunately I don’t . If anyone knows the methods and can share them would be very appreciated. Thanks.