The "D" input of the trigger is connected to the switch. If it is set to the logic source position, the trigger output is set to the same state at the positive edge of the clock pulse. If the switch is set to a position that connects the inverse output of the trigger to its "D" input then the trigger changes its state at each positive edge of the clock pulse (mode counter or frequency divider). The switch, resistors and LEDs are not part of the trigger structure.
