On the general tab, you will have to give your rule details like Rule order, Rule priority, Rule description. After that choose the Discount method "Quantity based by product/category and BOGO deals".
Step-2: Condition tab
After filling discount rule details, navigate to condition tab and define your discount conditions.
Step-3: Discount tab
Now move to Discount tab and set the discount quantity range and select your discount product.
Step-4: Frontend demo