For a little while, Windup Quickstarts could not build as they got out of sync with latest API.
That's over and now they build. Well, if you skip tests One of rules fails and I had no time to figure out why yet. But at least you can take the quickstarts as a basis for your rule.
Go and try: windup/windup-quickstarts · GitHub
Here's a script to get everything you need to start playing with Windup rules in Java syntax: Windup lab scripts