The Prophet ﷺ commanded that the hands be placed down and the feet kept upright.
حدثنا عبد الله بن عبد الرحمن أخبرنا معلى بن أسد حدثنا وهيب عن محمد بن عجلان عن محمد بن إبراهيم
أن النبي ﷺ أمر بوضع اليدين ونصب القدمين
[Its chain of transmission is hasan] Bayhaqi related it: 22/107, from the hadith of Wahib with the same chain, and Ibn Ajlan explicitly stated that he heard it directly, in his version. Muhammad bin Ibrahim is Taymi, and the hadith has corroborating narrations.