Upon arriving at مزدلفہ after sunset from عرفات, the first priority is combining Maghrib (3 rak'ahs) and Isha (shortened to 2 rak'ahs) نمازs. نبی کریم (صلی اللہ علیہ وسلم) combined these two نمازs at مزدلفہ with one adhan and two iqamas. This should be done soon after arrival — do not delay the نمازs unnecessarily to settle in.
The requirement for staying at مزدلفہ varies by school. The Shafi'i and Hanbali schools consider staying at مزدلفہ even for a moment after midnight as fulfilling the wajib (واجب act). The Maliki school requires staying most of the night. The Hanafi school considers the stay at مزدلفہ as wajib, and departing before Fajr without excuse requires fidyah. The strongest practice is to stay from arrival until after Fajr نماز, then depart for منیٰ before sunrise — this is the Sunnah of نبی کریم.
During the night, collect 49 pebbles (or 70 if staying in منیٰ for 3 days of Tashreeq) for the stoning ritual at جمرات. Pebbles should be slightly larger than a chickpea. Sleep under the open sky — there are no tent structures at مزدلفہ. Make دعا and dhikr, especially at the Mash'ar al-Haram area. The night at مزدلفہ is a profound spiritual experience of simplicity and equality, as all حجاج — rich and poor — sleep on the bare ground together.