If you have a Swatch Skin Chrono and want to reset the dials to point vertical after a battery change:
Press both buttons simultaneously, all three dials should spin 360 degrees
press the reset (bottom right) button, the 1/10th second hand should spin 360 degrees. Press the start/stop button (upper right) and you should see the 1/10th second hand move one click. Keep pressing the upper right button until the 1/10th second hand is aligned (vertical).
Then press the reset button. The second hand should spin 360 degrees. Set the second hand using the start/stop button, as above.
When you have set all three dials in this way, press both buttons simultaneously, and all three dials should spin 360 degrees.
Hope this information can be of use to someone.