DSXchange

I have derivation code and I would like to explain it as well within the derivation. How do I do it?

You can't directly there. Routine code can be documented, but for derivations you'll need to use either the General tab of the stage or put an annotation on the canvas.

I've found the latter works best as most peoples may never see the other.

Put an annotation outside the transformer on the canvas. You cannot put comments inside a transformer stage, as far as I know.