Musnad Ahmad 5:313

Marwan narrated to us, Abd al-Malik ibn Sila al-Hamdani narrated to us, from Abd Khayr, who said: Ali taught us the ablution (wudu) of the Messenger of Allah, may Allah bless him and grant him peace. The boy poured water over his hands until he cleansed them. Then he inserted his hand into the water vessel (rakwah), rinsed his mouth, sniffed water into his nose, and washed his face three times each. He washed his forearms up to the elbows three times each. Then he inserted his hand into the water vessel and submerged its bottom with his hand, then he took it out and wiped the other [arm] with it. Then he wiped his head with his palms once. Then he washed his feet up to the ankles three times each. Then he scooped a little water with his palm and drank it, then he said: "This is how the Messenger of Allah, may Allah bless him and grant him peace, used to perform ablution."