Let’s take for example the TAG Heuer Carrera CV2A10.Ba0796. This watch has a chronograph feature. The subdial at the 9 o’clock position displays the seconds for the watch. You have the large minute hand and the smaller hour hand. These 3 are used to tell the time.
The large second hand is used to tell the seconds for the chrongraph feature. The subdial at the 12 o’clock position tells the minutes for the chronograph and the subdial at the 6 o’clock position tell the hours.
To operate the chronograph feature this watch is equipped with 2 additional buttons. One at the 2 o’clock position and one at the 4 o’clock. The button at the 2 o’clock position is used to start and stop the chrongraph, while the button at the 4 o’clock position is used to reset the chronograph.