Fig 1
In order to determine the exact position of the button thread the central hole of the automatic button, you will have to make a stitch by sewing both sides of the cloth simultaneously and pulling the thread out of the hole itself, leaving a little slack, then cut.

Fig 2
Open the two opposite sides of the cloth, cut the thread in the centre, this will give you the correct position at which you will apply the two parts of the press studs.

Fig 3
Sew the male at the upper side and on the inside by passing the needle 3 or 4 times through the holes without letting the stitches go through the right side, make a knot and a small back stitch. Cut the thread. Place the female underneath and sew in the same way as you sewed on the male.