I'm a bit confused by your question, too, but I'll try to sort through it. The pronoun, You, is second person. Although, third person pronouns, He or She, wouldn't change the sentence construction. did(n't) add looks like a past perfect verb to me, with did being the helper verb to make it a perfect. Apparently, that claim could be disputed.
Whether to use didn't or haven't would depend on the situation. If the meal is already cooked, you'd say, "You didn't add salt to the meal." (Note: The way this sentence is worded, use article the before meal.) If the cook is in the process of preparing the meal, and adding salt is one of the steps, you'd say, "You haven't added salt to the meal."