Once you have completed a HUMANOO course, you can receive diamonds for it.
You can exchange these for cash and rewards in the webshop.
Here you can see how the bonus programme works and what you have to do to complete a course:
Afterwards you will receive a short instruction by email on how to get your diamonds. This email does not come automatically - as described in the article above from point 6 onwards, you have to trigger it under "Rewards".
The email contains a short instruction and a link to the form you have to fill in.