If you don't know any western music theory, you can just play around until you hear something you like.
If you do know music theory, you'll notice some intervals that have sharps and flats that normally wouldn't have them (like the 7th has a sharp which would make it an octave, or the 3rd has a sharp that would make it a sus4, blah, blah, blah). Anyhow, just kind of...forget your training and go with it. Seems to work best for ambient stuff.
Uses STOCK and Free modules.
Reason 12 Little LFO by Little IO
TMA-one commentator by Jiggery Pokery
ChordS is here:
Quick video is here: