For a basic tennis lesson, you want to instruct in how to hold the racket, possibly a western grip. Then you will wan to have a lesson about getting comfortable with hitting the tennis ball. You can have the ball hit higher so it is easier to hit.
You can hit an underhand serve in tennis; however, the overhand serve is more effective because it is more powerful. That is why you don't see the underhand serve used much.
a serve
Badly.
A tennis ball!
never draw back
It depends on how hard you want to hit the ball
a tennis ball
Let
Yes
A tennis ball.
a fault