Basically a switch layer is a folder that holds other layers. You right click in the time line to choose which layer is displayed. Or you can use the "Switch Layer" tool that is located in the layer tools section of the tool palette.
Make sure that any layers you want to use inside the switch are INSIDE the switch layer. You have to drag them in. Drag a layer over the switch and it should highlight red. Let go and the layer is now inside the switch.