If you load a song that doesn't have a scripted light show attached, this is where your Autoloops come in.
Autoloops is a backup system that works automatically when audio tracks without SoundSwitch Scripts are loaded into Serato DJ. They are designed to fit with the music structure and can be created in 8, 16, 32, 64 and 128 bar durations. There are four Autoloop banks with room for 8 Autoloops in each bank; 32 Autoloops in total.
In Performance Mode, Autoloops are synced to the Beatgrid in Serato DJ and will cycle through as you play. As an example, if you have created four 8 bar Autoloops with each being a different color, as the song plays through in Serato DJ, your lights will change colour every 8 bars in time with your Serato Beatgrid.