Tutorial refers to a 'stitching tutorial', this does not exist.
Because the stitch tutorial does not exist various sections of the tutorial need re-phrasing and a better explanation.
Provide API links to all functions mentioned.
Give more info about fold.
The aper[-2:, 0:2] = 1 definition does not make sense - should be [2:0, 0:2] = 1
When you compare the potentially contaminating bright star to the Kepler object you should use the same parameters in the way you plot and fold the light curve.