I. Threading: take a piece of thread and thread it by aligning one end with the seam of the sewing needle.

Two, alignment: take the needle of one hand and the thread of the other hand as the center, align the ends of the thread.

Three: Align the ends of the thread and knot around them so that the knot is as close to the bottom as possible.

IV. First Stitch: pass the needle through the back of the garment, aligning the seam allowance to be sewn through the buttonhole.

V. Second stitch: point the needle towards the outer edge of the buttonhole and place it on the back of the garment.

VI. Third needle: after placing the needle back on the back, place the eye of the needle into the loop formed by the sewing thread and tighten.

VII. Repeat: Repeat steps 4 and 5 several times. Remember, from back to front, the needle and thread need to go through the buttonhole, and from front to back, they need to touch the outer edge of the buttonhole.