Tell participants a little bit about why you were doing what you were doing, what was the purpose, what you expected to discover, etc. Provide clear, accessible, and sufficient information to your participants so that they can make an informed decision about whether to take part in your research.

Do not blind them with jargon – this should be written so that anyone can understand what you have done and why. Don’t exaggerate the importance of what you have done – you have not been looking for the  “Holy Grail” of such and such.