I can't get my midi file to load each track individually. All of the track will merge onto one channel. What do I do?

Assuming it is similar in the Mac version as the Windows version, MIDI files don't load into one channel, but they do all load into the melody track. If you use the Sequencer button, you can then see the breakout of the different channels on the melody track. Multichannel MIDI can reside in either the melody or soloist track, and you can move things back and forth between them.

But, MIDI files will not load a bass channel to the bass track, or a guitar channel to the guitar track, because those tracks are expected to be generated by the auto-accompaniment features.

That's the way it has worked for a long time.