The Self Timer mode enables you to trigger the camera after the timer goes off. It has a single parameter:
Timer: This parameter is used to set a timer. When the timer goes off, the camera will be triggered once.
The Self Timer mode does not have any exposure parameter. It will only trigger the camera for pulse length duration.
You can stop the mode by touching Stop button (Lock icon) 2 times. When you touch first time, the lock will be opened and when you touch it second time, mode will stop.