Decide what you would like your display to be, then shape the cardboard or wood to fit the display. You will use the cardboard or wood to hold your LED lights in place.
Use a pencil to mark where you would like to put the LEDs. The marks you make should be slightly smaller than the diameter of the LED, because you won't be putting the whole LED into the wood or cardboard.
Punch out the holes, or cut them out using scissors.
Put glue on the front of each hole and push the LED in from the front. When you push in from the front, the LED takes excess glue inside the hole with it, making your display look crisper. Repeat this with each LED, double checking to make sure the wire leads are available at the back. The wire leads are the long, metal pieces that stick out the back of the LED.
Connect the positive wire to the positive LED wire lead, and the negative wire to the negative LED wire lead. Ideally, you should do this by using a soldering iron, but simply stripping the wire and wrapping it around the wire lead may work.
Solder the positive wire to the positive end of the battery holder. Repeat this process for the negative end. Again, if you are unable to solder the wires, you can twist tie the wires around either end of the battery holder.
Insert batteries into the battery holder. This will turn on your LED display.