How did the Prophet, peace and blessings be upon him, comb his noble hair?

The Prophet, peace and blessings be upon him, used to comb his hair himself, or one of his wives would comb it for him, and he loved to comb it.

He forbade combing it except occasionally, meaning from time to time.

He might also let it hang down (sadl), or part it (farq). He used to let his forelock hang down, then he parted his hair after that.

Parting the hair (farq) is a Sunnah, and it is preferable to letting it hang down (sadl) because it was the last practice of the Prophet, peace and blessings be upon him.

The correct and chosen opinion is that both letting it hang down (sadl) and parting it (farq) are permissible, but parting it is better, and it is recommended, not obligatory.