1. Read the manual of the game to know about the functions and the behaviors of them.
2. Look on SmileBasicSource the section submissions->resources. There you can find lot of tutorials.
3. Start a simple game: pong, tic tac toe or rock paper scissor.
Try reading through my Guess the number game. KEY: 8E7Y33G4 It is designed with beginning programmers in mind and has a lot of comments (please excuse the type-os). Let me know if you have any questions.