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