The engineering GUI has not been finalized, but one of the ideas we had for it was to include a small callout for helpful text descriptions.
We may want to further iterate on that specific design (e.g., should some help text appear on hover? or would there be too much text? perhaps just a help menu or button that shows a static page of text, explaining the program? that would be easier to control)
For now, this issue should just list what things should go in any help text or documentation, so that we don't forget non-obvious things during development.