When you record another instrument onto one you've already recorded how do you keep track of your notes?

Question

I have a computer connected to my computer and my computer has a program to record different instruments in tracks but how do I harmopnize my music to what was recorded.

Answer 1

Three options I can think of.

1) You can look at the MIDI data and it will tell you which note events were recorded on your first track
2) Many MIDI sequencers have a notation feature which will translate data into notation
3) You are on your own! You should be able to know or figure out what you played by listening

Answer 2

You could just score your music as you go. If you don't read/write music, you're going to have to rely on midi data and your ears. But Roland makes a software that you can run from a keyboard to your PC that will score whatever you play as you play it. It might behoove you to get a basic working knowledge of sight reading.