Sayyiduna Mu'awiyah (may Allah be pleased with him) performed ablution in front of the people, as he had seen the Messenger of Allah (peace and blessings be upon him) perform ablution. When he reached his head, he took a handful of water, poured it onto his left hand, then placed it on the middle of his head until the water flowed, or nearly flowed. Then he wiped from the front part of his head to the back, and from the back to the front.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 273