Notice that the sensor ports are gray and are named "1", "2" and "3" and motor ports are black and are named "A", "B" and "C". All your sensors and motors get connected to these ports. Refer to the following image for how different components are connected to the RCX.

To connect the motors to the RCX you need to use the black wires with connector plates. A motor has eight speeds, and is capable of going clockwise or
counterclockwise and pulsing.

Attach one end of the wire to the motos and the other end to the black output port.

The side you attach the wire to can affect the direction of the motor. Notice a the small picture, that has been circled in red. The direction of the wire that is connected to the motor effects the direction in which motor turns when run in "forward" motion.

To connect the touch sensor to the RCX, you need to attach one end of the wire to the sensor and the other to the gray sensor port. Touch Sensor activates an On/off switch inside a LEGO brick.

The light Sensor already has a wire connected to it. Attach its plate to a gray sensor port. Light Sensor senses different wavelengths of light.

Another important element of the RCX is the LCD display. The utility of the LCD display can easily be over looked, but if utilized wisely, it can be serve you very well. Most importantly you can use your RCX to read the values your sensors are reading or the speed/direction your motors are running in by using the "Display" button. As you press display a small arrow at the edge of the LCD screen moves along letters A, B, C and numbers 1, 2, 3 giving you the corresponding display for the sensors or the motors. Refer to the following image for more on the LCD display. If your brick does not have a firmware on it, it will show a blank screen with a little man just standing still. If brick has the firmware installed, when you turn on the brick, it shows a clock displaying all 0's along with the little man.