You can do this after the dashboard subsystem is made, but before the actual design is done. If an object for the auto chooser doesn't exist, go ahead and make one (look in RapidCode for an example, the one called m_autonomousChooser). Then, create a method that lets you add an autonomous option to the chooser (one already exists in RapidCode). Then add a getter to grab the selected auto, and also a method that sets the default auto. Then, in RobotContainer, have the method getAutonomousCommand call the getter that you just wrote. Also, in the constructor of RobotContainer, call the add auto routine method you wrote to add some of the auto paths that we've made.
You can do this after the dashboard subsystem is made, but before the actual design is done. If an object for the auto chooser doesn't exist, go ahead and make one (look in RapidCode for an example, the one called m_autonomousChooser). Then, create a method that lets you add an autonomous option to the chooser (one already exists in RapidCode). Then add a getter to grab the selected auto, and also a method that sets the default auto. Then, in RobotContainer, have the method getAutonomousCommand call the getter that you just wrote. Also, in the constructor of RobotContainer, call the add auto routine method you wrote to add some of the auto paths that we've made.