Help CenterVELUX skylight reset buttons are located on the interior frame of the skylight on the bottom, right-hand side. It is best accessed by inserting the end of a paperclip. Hold the reset button for 10 seconds to completely reset the skylight.
For reference, the larger hole pictured at the top of the first two images (in the middle with the white washer around it), is on the center of the skylight sash close to the glass.