Import the SmartDashboard package,
Code:
import edu.wpi.first.wpilibj.smartdashboard.SmartDashboard;
And then in wherever you want to print stuff, use the putNumber() or putBoolean() or putString (look in API for all things you can put).
For example;:
Code:
double test = 4;
SmartDashboard.putNumber("Test", test);
That should automatically print the data to the SmartDashboard when you enable.