Ripples have been popular in crochet for at least 60 years, and there are dozens of ways to make them. But basically it’s just a series of alternating increases and decreases, creating a zigzagging fabric. Here’s a video for one kind of Ripple Stitch!
This pattern would be written as such:
Ch3 and dc in the same stitch. Dc in the next 8 sts. Work dc2tog over the next three sts, by skipping over the center st. *Dc in the next 8 sts. 3dc in the next st. Dc in the next 8 sts. Work dc2tog over the next three sts, by skipping over the center st.* Repeat from * to * until there is one stitch remaining. 2dc in the last st.
I hope this gives you a good idea of how ripples come together in crochet!