Ibn Qayyim in his book “The Medicine of the Prophet” mentions consuming ground black seeds with honey and water, heating seeds with vinegar, and drinking black seed oil with water; while in Ibn Majah Vol. 4, Book 31, Hadith 3449, it mentions using 5 or 7 ground seeds with olive oil. You can follow these methods or simply chew them.
Black Seeds can be taken in both large or small quantities, as there are no upper or lower limits. However, the more you take, the more healing you will receive. Taking 7 seeds, 3 times per day, is a good starting point.