It helps if you break game projects up into smaller bits that you can manage to code.
Ok, you'll need:
2 paddles, either boxes drawn on screen, or sprites, or 3d objects.
One paddle controlled by the player, using the mouse/keyboard/joystick.
The other paddle controlled either by more player controls or by the computer.
A ball, again a circle drawn on screen, or a sprite or a 3d object.
A way to make the ball move (I suggest velocity variables).
A way to make the ball bounce off the sides of the playing area.
A way to make the ball bounce off the paddles.
A way of detecting if someone has missed the ball, and a game restart afterwards.
A points system.
Is that enough of a start? There's no set place to start, but it is helpful if you have completed some of these bits before you embark on others.
Once I was but the learner,
now, I am the Master.