If a person understands their abilities and talents and improves them lifelong, that would be their function. Aristotle describes the function of the meaning as the “exercise of his vital faculties.” The exercise of the faculties could be reached when a person uses two sides of their nature. One side corresponds to rational thinking, and the second one obeys the first one. Exercising faculties should take quite a long time because short actions or short-time happiness do not contribute to a happy life as a whole.
For example, if a person is talented in singing, singing once a time in a month would not make them happy. A person will not exercise his vital faculty because he does not imply a rational attitude towards improving their abilities and does not benefit from them. They will not be able to obtain happiness from such a short period of action. It is crucial to dedicate time and be consistent with the vital faculty if you have one.