To start a live Jam, select Jam from the Main Menu. From there select your Jam, Venue, Controls, and Duration in the menus.

The core musical component of Just JAM is the Jam: a set of five different Instrument Banks, each containing five tracks. All of the tracks within each Jam are designed to work together. By controlling when each track plays you will create your own unique song with each Jam.

Tracks come in two different types: looping tracks and one-shots. Looping tracks make up the majority of most Jams and synchronize with each other automatically, so no matter when you start a looping track it will play perfectly on beat. Once started, looping tracks will continue to play until you turn them off. Looping tracks look like .

One-shots work a bit differently. One-shots start at the beginning whenever you play them and only play a single time. Because one-shots don't synchronize automatically like looping tracks, it is up to you to play them on time and on beat with the rest of the music. One-shots in a single bank are meant to be played one at a time, so starting a new one-shot will automatically stop other one-shots currently playing in the same bank. One-shots look like .

When a large number of tracks are playing at once it can be difficult to tell which track is making which sound. To help sort the Jam out, each track has its own volume meter on the outside of the track icon.