This is the like the equivalent of a Sleeper in 1A. The Windmill is the most basic 5A trick there is and the first stepping stone to a whole new style of play.
Start off with a breakaway and stick your non throw hand index finger out like you’re going to land a Trapeze. Instead of mounting the yoyo on the string you’re going to let the counterweight go, let everything rotate around your finger, re-catch the counterweight in your throw hand.
This trick is going to be your first lesson in understanding counterweight momentum. There are many factors that go into how quickly the counterweight is going to come back to your hand, like: string length, weight of the counterweight, weight of the yoyo, and how hard you through, to name a few. This is 5A 101 and it’s not a difficult trick to land, but check out the tutorial again to see how it’ done well.