This stage can be solved with wiring alone.
Press a terminal (the small ◯) to start a wire. Press where you want to bend to place corners, and finish on another terminal or on a wire. Press the middle of a wire and then somewhere else to draw a branch from there. You can drag parts and wires to move them. When you are ready, press "Run!" to turn on the power, and try the switches while it is on.
Wheel to zoom, right-drag to pan