Using the Triathlon mode for the first time may be quite challenging for people who have never dealt with this before. Thus, just pick the triathlon mode, then there appears a one-time picture that shows which buttons will be involved in this mode. There are 4 data screens that can be switched by pushing the “down” buttons on the watch edge. Just make sure that the smartwatch  is connected to GPS (the data screen will be active), and then you can push the button to launch the timer.