Your project will look nicer if you make the hole from the front of the board and then insert the LED from the back side of the cardboard or foamcore of your project. The wires are also less likely to get crossed when they lay flat on the board, neatly folded over from the back of the LED. Avoid pushing the LEDs all the way through the cardboard or foamcore.
A quick way to test your sensor connections, LEDs and wiring is to attach a working 9 volt battery to the MakerBit. All the LEDs should blink several times. Then, touch each sensor in turn, 5 through 16. When you touch each sensor, the matching LED number should light up. If nothing works or one of the LEDs doesn’t light up, see our Technical Support page.