To do this stitch, you should be aware of the twisted chain stitch.

This stitch is a series of twisted chain loops. The difference being that the stitches are placed on the left adn right sides alternately. So, the ‘legs’ of  the stitches will fall on the left side and the right side of the stitch line alternately.  I will follow a straight stitch line to make this lesson clear.

alternating_twisted_chain_1   alternating_twisted_chain_2
Fig 1: Lay the base by doing a twisted chain stitch.   Fig 2: Now, put the needle in through the right side of teh previous stitch and bring it out on the stitch line, as shown.
alternating_twisted_chain_3       alternating_twisted_chain_4
Fig 3: Loop the thread around the needle as illustrated.   Fig 4: When you pull out the needle and tighten the loop, you will get a twisted chain loop with its leg on the right side.
Fig 5: Continue with this process of making twisted chains. Remember to alternate the sides by taking the needle in on the left side once and the right side the other time. You should get a pattern that looks like the one above.