Step 4: Build the LED circuit...
1. Wire all of the negative terminals of the LED's together for each letter
2. Add a 330ohm resistor to each positive LED terminal and wire all of the positive leads together.
3. Join the positive contacts and negative contacts of each letter in the word to form a group or section that you want to flash.
4. Build the flashing circuit and hot glue it in place. Add your 9 Volt batteries, 1 or 2 to power the LED's and 1 to power the circuit. I found that one would light the sign for a long time and the LED's will run on as low as 4 volts.