Humran reported,

Ati reported that he saw Uthman call for water for ablution. Uthman poured water from the vessel over his hands and washed them three times. Then he dipped his right hand into the water, rinsed his mouth, and sniffed water into his nose. Next he washed his face three times, then his arms up to the elbows three times each, then wiped his head, then washed each foot three times.Afterwards he said, "I saw the Messenger of Allah ﷺ perform ablution just as I have done. Then he said, 'Whoever performs ablution as I have done, then stands and prays two units of prayer without letting his mind wander during them, Allah will forgive him his past sins.'"

Nasai 85

Sahih

أخبرنا أحمد بن محمد بن المغيرة قال حدثنا عثمان هو ابن سعيد بن كثير بن دينار الحمصي عن شعيب هو ابن أبي حمزة عن الزهري أخبرني عطاء بن يزيد

عن حمران

أنه رأى عثمان دعا بوضوء فأفرغ على يديه من إنائه فغسلها ثلاث مرات ثم أدخل يمينه في الوضوء فتمضمض واستنشق ثم غسل وجهه ثلاثا ويديه إلى المرفقين ثلاث مرات ثم مسح برأسه ثم غسل كل رجل من رجليه ثلاث مرات ثم قال رأيت رسول الله ﷺ توضأ وضوئي هذا ثم قال من توضأ مثل وضوئي هذا ثم قام فصلى ركعتين لا يحدث فيهما نفسه بشيء غفر الله له ما تقدم من ذنبه

النسائي 85صحيح
Contents
Reference
Commentary
Ayat
Collection
Sunan Nasai Sughra
Book
Purification
Chapter
Rinsing the mouth with which hand
Numbering
Darussalam 85
Nasai 85