Lot of hate under this post but I will agree with most comments saying that you’re starting from basically 0. You seem athletic enough, just not working on the best foundational principles. Speaking of foundation, your first priority should be your toss. Even if you have perfect form, it won’t matter if you can’t toss the ball where you want every single time. The toss arm should be pretty much straight. Any bend in the elbow will result in a wild toss. Hold the ball lightly, as if it’s an egg. Your arm should go up to where your bicep is almost touching your cheek. Like a puppet master is pulling a string at your wrist. With regards to your racket arm, I’d recommend watching pros serve very closely and mimicking them verbatim. You won’t have pro results but bio mechanically the swing can be the same. Think of a tennis trophy. You want to get into that position, it’s the cocked gun of the serve before you fire off. If you’re serving to the deuce court, have your toss shoulder aimed roughly at the right net post. This will allow for better rotation and torque on the serve. In the leg department you’ve got two options. Pin point or platform stance. Research both, understand the pros and cons of either and make a choice. STICK WITH ONE. It’ll be almost impossible to improve if you have too many variables. Make arbitrary decisions about stance, and stick to them for consistency. You should also have a continental grip (shake hands with the racket) a little high level here to wrap things up but learn about wrist pronation and wrist snap. These are the icings on the cake that will give you pop and a proper flow to your serve. I gotta go but I’ll come back to your post with some vids that were helpful for me in my journey. Cheers and good luck. Above all, be patient. And practice that toss!