Zigzag chain stitch as it's name suggests is chain stitches that are worked at an angle to the previous stitch to create a zigzag effect. They can be worked in lines or around a shape to give an interesting edge. When working zigzag chain stitch it is important to keep the stitches even. I recommend working between two parallel guidelines.
Bring your needle up at 1, then insert it back again at 1. Bring your needle up again diagonally at 2, as shown, looping your thread beneath your needle pull through gently.
Next make another chain stitch by inserting your needle at 2 again and bring it out diagonally at 3, looping your thread beneath the needle pull through gently.
Work back again to the right by inserting your needle at 3 and bringing it out at 4. Looping your thread beneath the needle pull through. Continue working chain stitches from right to left as required finishing the last chain with a small stitch as for chain stitch.