GarageBand Version: 1.2 Review | iPhone and iPad Music App | Macworld: This works very much the way you’d play a collaborative game. Each member of the “band” must be on the same local Wi-Fi network. (If Wi-Fi isn’t available, you can also hold a jam session over Bluetooth.) One member of the group taps the Jam Session button that appears at the top of the GarageBand screen and becomes the leader and has control of the song’s key, chords, and tempo. The leader then taps Create Session. The other members of the band tap their Jam Session buttons and, in the Join Session area of the resulting window or screen, tap the name of the iOS device that the leader is using. They’re now part of the session. (The leader can boot anyone they wish to by tapping on a member’s name.)