Video tutorial here :

Ch a multiple of 3 plus 2.

Foundation Row: [Puff st, ch 2, puff st] in 6th chain from hook, *ch 1, skip 2 ch, [puff st, ch 2, puff st] in next ch, rep from * across to within last 2 ch, ch 1, skip next ch, 1 dc in last ch, turn.

Row 1: Ch 1 (counts as first sc), sc in next ch-1 space, * 3 sc in the ch-2 space, 1 sc in next ch-1 space, rep from * across, sc in top of the turn ch, turn.

Row 2: Ch 4 (counts as dc, ch 1), skip first 3 sc, [puff st, ch2, puff st] in next sc, * ch 1, skip 3 sc, [puff st, ch 2, puff st] in next sc, rep from * across to within last 3 sts, ch 1, skip 2 sc, dc in top of turning ch, turn.

Rep Rows 1 and 2 for pattern.