Simple Midi Problem

I'm using a Yamaha MM6 keyboard and sequencing it with the 1000. the problem I'm having is that I can only record one "sound" per sequence. For example, I'll record piano on track one of a sequence, and then, I'll record a synth on track two. this makes the piano track play the same thing but with the synth sound that the MM6 is currently on. Basically, I just wanna record a sequence with more than one sound lol. I'm sure I'm making a simple mistake, so if someone knows the answer to my problem I'd really appreciate the advice.

thanks in advance,

greeny