Once the first side is finished, repeat for the back side;
Wire the tubes together in series; from the transformer to the first tube, through the rest of the tubes and back to the transformer again. Plug it in to make sure everything works before you hang it.
Next, find a volunteer to climb the ladder. (May have to promiss him a couple beers after he gets done.
Make sure the sign is supported, the wiring is correct and nothing will fall against the tubes.
Finally, plug it in and enjoy the glow and buzz of the neon.