If all you want do do is display and send numeric data (or use one of the built in widgets), you don't need to code anything for SmartDashboard. All you need to do is call SmartDashboard.putNumber early in the code (so that it pops up in the SmartDashboard) and then SmartDashboard.getNumber to retrieve the number from the SmartDashboard.
There's some documentation about the SmartDashboard here:
http://wpilib.screenstepslive.com/s/3120/m/7932