In the past, getting the lights hung on the house and plugging them in without having a bulb burn out was a major accomplishment. In the modern world of technology, your entire Christmas light display can be controlled by a computer and run the gamut from dancing designs to talking animatronics. The systems to create such shows are now widely available and almost anyone can have their whole light display dancing in tune to Christmas carols.
Plan, plan, plan. This type of display can be a plug-and-go experience if you purchase a kit already programmed that merely requires adding your strings of lights. However, you still need to know how many strings you can attach, where they will go and in what sequence they will fire. Those are the easy systems. In creating your own display to arrange and program, you need to know every little detail before one light string is even hanging from your eaves. Draw a diagram of the lights and extension cords, which is doing what and where it connects to before you begin.
Follow your diagram and start with the furthest lights from the controller--this prevents a tangle of wires. String the lights, connect to the extension cord and then add any others that are on that relay. Using multiple light strings means you need to distribute your power so that you don't blow a fuse, so be sure to use outdoor connectors or draw power from different areas to handle the load.
Connect the lights you run to the controller box. Run the USB cable from the controller box to your computer. You will need a cable that's long enough to extend indoors, where the computer will be run. In cases where people do this as a yearly event, they often set up a dedicated PC in the garage or somewhere in the front window of the home that is used only for the lights. Do a test run on the lights once everything is connected.
Create your lighting and music sequence. This is the part that can be somewhat technical but makes the display the most fun. Depending on the unit you purchased, there may be preset sequences you can use, or you may be able to create your own. You can add whimsy and fun by choosing music that has characters and by using parts of your display such as individual trees to fire when those characters speak. Any theme or mood can be achieved in this part of the set up, and you can create multiple sequences to use at varying times.
Install the FM transmitter. This is a device that will broadcast your music directly to the cars of those driving by your display.
Make any necessary tweaks or adjustments after your system is up and running.