Method 1
Secure the chain of the beginning and the end of
a stitch with your machine.

At the beginning of a stitch

1. Sew a few stitches, after chaining-off for 5cm(2 inches).
   
2. Stop the machine and raise the presser foot.
   
3. Put the chain under the presser foot, and serge over it pulling toward you.
   
4. After sewing a few stitches, cut off the extra chain with the knife as illustrated.

At the end of a stitch

1. At the end of the seam, sew one stitch out of the fabric before stopping the machine.
   
   
   
2. Raise the presser foot and the needles, then reverse the fabric.
   
   
   
3. Lower the needles and the presser foot at the same position.
   
4. Serge over the seam, taking care not to cut the serged seam with a knife.
   
5. After sewing a few stitches, serge off the fabric as illustrated.
   
   
   
6. Cut the threads with scissors.

Method 2
WIth this method, the chain of the beginning and the end of a stitch can be secured in the same manner.

1. Tie the thread unpicked from chain.
   
   
   
2. Insert the chain into the end of the seam, using a hand sewing needle with large eye.
   
   
   
3. Fix the chain with a drop of fabric glue, and cut the extra stitches after drying.