There are many YouTube videos to be found on this topic by simply searching with search words like this: "piano posture hand position". Try a few of them out (many of them are only a few minutes long) and practice using their guidance as you go through the course. If you find one you especially like, you might want to bookmark it so you can review it again after a short period into the course.
Of course, if you have friends or family that play the piano, they will happy to critique your style! Honestly, they can be very helpful and can answer your questions. This remains true throughout this course when it comes to playing technique. However, they are not going to understand this new notation... and not likely to approve of it.