Please follow the steps below:

- Create a Products List with the selected products or product category.

- Create a Pricing Rule, select Discount Type 'Quantity Based Discount', select the created Product List or set to ALL (if you wan to apply the discount on all products).

- Under 'Quantity Based Discount', we do have 3 options:

 - Discount on individual product quantity:- For applying discount when a user purchases multiple quantities of the same product

 - Discount on cart items count:- For applying discount when a user have multiple items (separate products) in the cart, here individual product quantities will not be considered

 - Discount on cart quantities:- both individual quantity and cart items will be considered, For Ex: You have 3 A and 4 B in the cart, it will consider the count as 7

- Select the desired quantity discount type 

- Set the quantity parameters (set min and max quantities, discount type, value)