Pass the needle through the horizontal yarns, alternating over and under each row.

After passing through all rows, pull the yarn through to create a vertical line of yarn, then make a horizontal stitch at the top to secure the yarn.

Then move back across, weaving the needle over and under the rows in the opposite way.

Repeat this process, alternating over and under with each pass and securing each pass with a small horizontal stitch.

See the next two steps for detailed videos of this technique.