Let's say I want to give discounts on products from 3 collections (and 3 product types - the product type will serve here as the restriction to TRIGGER the application of the automatic discount). Let's take a real example.
Collection A = Shoes
Collection B = T-Shirts
Collection C = Pants
To keep things simple, the product types of all the products inside a collection will be the same as the collection:
Collection A Product type = Shoes
Collection B Product type = T-Shirts
Collection C Product type = Pants
When you create the discount, make sure you select the products (or the collection actually) you want the discount to apply on. (You can even set a minimum purchase $ required, it's usually better).
Discount A = 30% on collection Shoes
Discount B = 40% on collection T-Shirt
Discount C = 50% on collection Pants
Exemple of Discount A below:
Then, inside our Automatic Discount app, create the rules, like that. You can use another rule like "#number of items" or "# number of similar items" in the cart, or the "Amount in the cart" :
And then make sure to create an additional restriction to trigger only when the specific product of the specific product type (eg. Product type being "Shoes" for Discount A).
If you don't know where the "Product type" can be set, go in the "Products" section and enter the product page. At the right, there is a field called "Product Type".
Overall, you discount rules should be from the biggest discount at top to the smallest discount at the bottom, so from Discount C at top to Discount A at the bottom.