Pickleball Rules Refresher: Serve motion

The serve can easily be very disputable in pickleball, and so it should. The serve sets the tone of how the game will be played, and letting someone serve illegally needs correction. I've seen some people that will move their body in such a way that their whole body is slanted to get in an optimal serve position. But for most of us that serve normal what is legal, and what's illegal? The IFP rules state,  4.A.  Serve Motion. The serve must be made with an underhand stroke so that contact with the ball is
made below waist level.
                            4.A.1.    Underhand Defined. The arm must be moving in an upward arc and the paddle head shall be below the wrist when it strikes the ball.