In the menu screen, press [L, M(left/right)] button to select the timer category, and press [OK] button to move to the timer setting list screen.
In the timer setting list screen, press [J, K(up/down)] button to select the timer to set, and press [OK] button to move to the detail screen.
After setting the value, when you press [OK] button, the timer is activated.
After setting the value, if you press [Back] button, the changed value will not be applied.