To move Player 1 up and down press W and S keys. To move Player 2 up and down press up and down arrow keys. If the ball touches the blue rectangle, it will bounce. If it touches one player's line, other will get a point.
Credits to my academy which taught me scratch. You can see my other small but wonderful projects on- https://scratch.mit.edu/search/projects?q=TalentedProjectMaker