It’s because it’s almost the same steps as a curly routine but different products. Wavy hair uses a bit more lightweight products than curly hair. So for shampoo and conditioner definitely use a nice moisturizing or curl enhancing one, sulfate free is usually the best kind of shampoo, if you use one with sulfates best not to use it all the time. And leave in conditioner is great for keeping it from getting frizzy and providing moisture and mousse to hold the waves in place, you could use a gel
Some great products for shampoos and conditioners are from the lines sheamoisture, not your mother’s, and even Maui. For products not your mothers has great products like their leave in that’s lightweight and wont way down your waves so they won’t be dull. They have a great defining mousse. Garnier has great curl enhancing products have well.
Here’s the order you would need to go in, it’s about layering the products and making sure you provide enough moisture in the hair because moisture is what will help hold the curls. After shampoo and conditioner and out the shower, use a leave in, mousse, and a little bit of gel if you want. Rake each product into the hair with fingers and then scrunch into the hair to form the waves, and you could either plop the hair to dry so wrapping it in a cotton shirt or you can diffuse it.