In Self-Made Discounts, click on Create Discount to view the discount list. You can select the discount type, such as:

Item or Quantity Discounts
Buy X, Get Y (e.g., Buy 2, Get 1 Free)
Exact Quantity
Customer group
Free Delivery
Minimum Quantity

You can then apply various rules and restrictions to each discount type. Set the discount as either a percentage or flat amount, and define the amount, validity period, and minimum spend conditions.