In this pattern, you create a selvage by knitting into the back loop on every first stitch and slipping every last stitch. You can see the selvage pictured below.
The next stop involves picking up and knitting 1 stitch for every selvage stitch on the edge. Do this step with the wrong side of the garment facing you. Cast on 3 extra stitches at the end of the row. I used the backward loop cast on method.
Next, knit 2 stitches, then knit 2 together through the back loop. THEN, slip all 3 stitches back to the left needle.
Then, bring the yarn across the back and repeat the sequence knit 2, then knit 2 together through back loop. After each set of 3 stitches, slide the stitches all back to the left needle. When you reach the last 3 stitches, bind off. You can see the i cord edge forming in the last picture.