Hi Roy,
I don't believe there is documentation about that, it has been a long time ago I already posted that Idea.
You can vote on it, I also reminded OutSystems again that this is a much appreciated documentation that they could provide.
https://www.outsystems.com/ideas/7407/instructions-on-how-to-include-existing-reactjs-ui-components-as-custom-component/
Regards,
Daniel