mBox only lets you record 2 channels at a time. If you have more than 2 sources at a time you'll need to mix all of them down to 2 channels (i.e. left and right) using a mixer. Otherwise, if you can get everything recorded into protools 2 tracks at a time, use the software mixer to mix your final mix. If you don't like mixing with a mouse, Behringer makes an inexpensive Control Surface that can control the software mixer in protools.