First of all, I suggest you choose a training course sponsored by a regular sports school or a government gymnasium. Then consult a professional coach first. Generally, he will ask about you (that is, your basic tennis situation), and even try your level with you, and then give you some advice. You just have to follow his advice. Of course, it depends on whether people are enthusiastic about you.

Secondly, if you want to omit the above procedures, decide for yourself, and I suggest you start with the basic courses. Many tennis lovers (more than 90% to be exact) basically gave up after buying a tennis racket for three months, because compared with other ball games, tennis requires strong coordination of the whole body, comparable to gymnastics, and it is difficult to get started. People who can survive the first three months and keep practicing for more than two hours every day need great perseverance. Starting from the basics will make you progress faster.

If you have mastered it, I think you should learn it from the basic course, because most amateur strokes are flawed. Forehand, (especially) backhand (divided into topspin and backspin), volley ball, serve and high pressure ball are all very complicated, and there is a difference between running and hitting, so you should lay a good foundation.

In short, perseverance is the true meaning of tennis. Stick to it, he is the real king in ball games, especially when your legs collide with each other during hitting the ball, and that feeling will make you unable to extricate yourself.