During development and practice, you choose between Autonomous and Teleoperated by using the Driver Station switch. During competition, the Field Management System will control the mode.
The Basic Get Mode VI in the LabVIEW code provides a way to read the competition state. Feeding it into a
case structure lets you do different blocks of code depending on whether the state is Autonomous or Teleoperated.
You can find this information (and a lot of other important facts) in the
Using the LabVIEW FRC Framework document, which is linked to on the
http://www.usfirst.org/frccontrolsystem page.