كتاب الحيض
3  
The Book of Menstruation
(9)
Chapter: Description of ghusl in the case of janabah (sexual impurity)
(9)
باب صِفَةِ غُسْلِ الْجَنَابَةِ ‏
Sahih Muslim 316 d

'Urwa has narrated it on the authority of 'A'isha that when Allah's Messenger (ﷺ) took a bath because of sexual intercourse, he first washed his hands before dipping one of them into the basin, and then performed ablu- tion as is done for prayer.

وَحَدَّثَنَاهُ عَمْرٌو النَّاقِدُ، حَدَّثَنَا مُعَاوِيَةُ بْنُ عَمْرٍو، حَدَّثَنَا زَائِدَةُ، عَنْ هِشَامٍ، قَالَ أَخْبَرَنِي عُرْوَةُ، عَنْ عَائِشَةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم كَانَ إِذَا اغْتَسَلَ مِنَ الْجَنَابَةِ بَدَأَ فَغَسَلَ يَدَيْهِ قَبْلَ أَنْ يُدْخِلَ يَدَهُ فِي الإِنَاءِ ثُمَّ تَوَضَّأَ مِثْلَ وُضُوئِهِ لِلصَّلاَةِ ‏.‏
Reference : Sahih Muslim 316d
In-book reference : Book 3, Hadith 43
USC-MSA web (English) reference : Book 3, Hadith 619
  (deprecated numbering scheme)