You must start by choosing a racket. Rackets vary in size in color. Depending on how tall and big you are will detirmine your racket size.
After, that you would need some tennis balls. Some people prefer brand new ones if you are playing a match and others do not have a preference.
Then, you must choose an outfit. Depending on how fashionable you want to be you basically just need any sort of athletic wear. For girls, I prefer to wear a tennis skirt with soem sort of tight fitting shirt. You must then find the right shoes. It is smart to buy shoes that were made specifically for tennis.
When you have finsihed finding the right outfit and getting the right equipment you are ready to hit the court.
A serve is the starting point for a match. This could be one of the most important shots of a match. To make a serve you must throw the ball up in the air and proceed to hit it to the opposite side of the court in your opponents box. After that, your opponent will return your serve and the rally begins.
The forhand shot is with your dominanat hand, either right or left, and you hit it one handed and follow through. This is usually the easiest shot to make during a match.
The Backhand is the shot you make with the not dominant side of your body and you use both hands to follow through. Some people prefer to just use one hand but begginners usully start off by using both.
A volley is made when you go up to the net and hit the ball without it bouncing first. There can be a backhand volley or a forehand volley.
A match consists of sets which have 6 games in them and in each game there are points that depend on how the game goes. You must win 2/3 sets to win a match. Down below I have linked a video from youtube to help you beter understand.