Use arrow keys to navigate the menus, 'z' or enter to select menu options. 'Esc' or selecting back button will take you back in the menus. You use right and left to select different settings on many buttons (Can not yet see what buttons that is valid for, but future version should have that).
Default are: arrow keys to move and 'z' for stop volley, 'x' for hit and serve toss and 'c' for lob. This can be configured from the game.
There are two different types of serves:
The Easy serve setting is good if you are new to the game. The Advanced serve setting makes it possible to serve harder, but also put you in a greater risk at making double fault.
Watch out for foot fault.
Use the practice court to perfect it.
The graphics routine is not complete, so swapping between other applications and the game can make players invisible... If repaint of the game screen is needed, press the 'R' key to redraw (you might have to press a couple of times). E-mail me if you want to help out with the graphics routine.
Are you experienced with 3D graphics?