You are viewing this pattern in UK terms.
Round 1: 3dc into 2nd ch from the hook, 1dc into next 6 ch, skip 2 ch, 1dc into next 6 ch, 3dc into last ch. The next stitches will be worked along the back/bottom of the chain. 1dc into next 6 stitches, (dc, ch2, dc) into ch2 space, 1dc into next 6 stitches. Place stitch marker into the last stitch to make the end of the round.
Round 2: 2dc into the first 3 stitches, 1dc into the next 5 stitches, skip 2 sts, 1dc into the next 5 stitches, 2dc into the next 3 stitches, 1dc into the next 7 sts, (dc, ch2, dc) into ch-2 space, 1dc into last 7 stitches. Mark your last stitch with your stitch marker.
Round 3-5
Round 3: *2dc into next stitch, 1dc into next stitch* 3 times, 1dc into next 4 stitches, skip 2 stitches, 1dc into the next 5 stitches, *2dc into next stitch, 1dc into next stitch* 3 times. 1dc into next 7 stitches, (dc, ch2, dc) into ch-2 space, 1dc into last 8 stitches. Mark your last stitch with your stitch marker.
Round 4: 1dc in first stitch, *2dc into next stitch, dc in next 2 stitches* 3 times, 1dc into next 2 stitches, skip 2 stitches, 1dc into next 4 stitches, *2dc into next stitch, 1dc in next 2 stitches* 3 times, 1dc into next 8 stitches, (dc, ch2, dc) into ch-2 space, 1dc into last 9 stitches. Mark your last stitch with your stitch marker.
Round 5: 1dc in next 2 stitches, *2dc into next stitch, 1dc into next 3 stitches* 3 times, skip 2 stitches, 1dc into next 3 stitches, *2dc into next stitch, 1dc into next 3 stitches* 3 times, 1dc into next 9 stitches, (dc, ch2, dc) into ch-2 space, 1dc into the last 10 stitches. Tie off using the invisible seam technique.