You have power to the switches.. That's a good thing. Do you have power out of the switches? If not the switches may be bad. If you have power out of the switches check the power at the light. If you have power there, too, the bulb is probably defective. If you have no power to the bulb trace the wires for a break or a bad connection. You don't really need a diagram to do this. A meter or test light can be a big help.