I spread out the top dress layer so I could trace some paths for the LEDs on the inside. I wanted them to look like strings of lights wrapped around the trees, so I mapped out diagonal paths for each color. The circuit ran from one shoulder around and around the dress and ended at the hem where the batteries would be connected.The hash marks indicated where the LEDs would be positioned.
Next I pierced the LED legs through the felt and spread them so all of the positive and negative leads would all face the same direction respectively. (If you have zero electronics knowledge, just make sure the short legs are all pointing in one direction and the long legs are all pointing in the other. The long legs connect to the + side of the battery pack.)