Mu'awiyah performed ablution before the people, as he saw the Messenger of Allah ﷺ performed ablution. When he reached the stage of wiping his head, he took a handful of water and poured it with his left hand over the middle of his head so much so that drops of water came down or almost came down. Then he wiped (his head) from its front to its back and from its back to its front. (Using translation from Abū Dāʾūd 124)   

أَنَّ مُعَاوِيَةَ تَوَضَّأَ لِلنَّاسِ كَمَا رَأَى رَسُولَ اللهِ ﷺ يَتَوَضَّأُ فَلَمَّا بَلَغَ رَأْسَهُ غَرَفَ غَرْفَةً مِنْ مَاءٍ فَتَلَقَّاهَا بِشِمَالِهِ حَتَّى وَضَعَهَا عَلَى وَسَطِ رَأْسِهِ حَتَّى قَطَرَ الْمَاءُ أَوْ كَادَ يَقْطُرُ ثُمَّ مَسَحَ مِنْ مُقَدَّمِ رَأْسِهِ إِلَى مُؤَخَّرِهِ وَمِنْ مُؤَخَّرِهِ إِلَى مُقَدَّمِهِ