OK, this isn't as complicated as it sounds. It really takes more patience and imagination than it does skill in electronics or computers. Here is the basics of how this works. The computer runs a piece of software called a sequencer. This sequencing software is responsible to telling which strands of lights come on at a certain point in the musical selection. Here is where the patience comes into play. It roughly on average will take 2 hours of sequencing for each minute of a song. So for a 4 minute Christmas song, it will take you on average 8 hours to sequence the song. The complexity of the sequence is all depending on the amount of lights you have and your imagination.

Computer running sequencer

Once the computer has songs sequenced, we need to be able to hook the lights up to the computer. This happens with some hardware modules which can be made on your own or if your not skilled in electronics like myself, purchased from vendors online. There are a few vendors whose products you can choose from. All do primarily the same thing, fade up and down, shimmer, twinkle, and turn the lights on and off. I use the Light O Rama brand and I find their support to be top notch. The board will accept the commands from the computer sequencer and control the lights that are plugged into them. You can see the controller below and the extension cords plug into them.

Picture of a LOR controller

From this point you would hang your lights and plug them all into your controller modules. This is the easy part. The hard part is already done assuming you have created your sequences.

Picture of cords coming in my window

And the mess being my computer