The beginning of stoning the Pillars, how it is to be done and the Number of Stones

Question :

When does the Hajj pilgrim begin stoning the pillars? How is the stoning done? What is the number of stones? Which of the pillars should be stoned first and when does the stoning end?

Answer:

The person stones the first of the pillars on the day of the 'Eid, and it is the pillar that is nearest to Makkah. It is called Jamaratul-'Aqabah. He stones it on the day of the 'Eid and if he stones it during the last half of the night on the night before the day of Sacrifice, that is sufficient. However, it is better to stone it at Dhuha time (i.e., after sunrise and before noon) and the time for stoning lasts up until sunset. If he misses stoning it before then, he may stone it after sunset during the night on the day of the 'Eid. He throws the stones one at a time and he says *Allahu Akbar' (Allâh is the Most Great) with each of the stones. In reference to the days of At-Tashreeq, he stones the pillars after the sun passes its meridian (after midday). He stones the first pillar, which is next to Masjidul-Khayf, with seven stones, and he says 'Allahu Akbar' (Allâh is the Most Great) with each of the stones. Then he stones the middle pillar with seven stones and then the last pillar with seven stones. This is done on the 11th day, the 12th day and likewise on the 13th day for whoever is not in a hurry to leave. The Sunnah is to stand after the first and second pillars. After he stones the first pillar he stands facing the Qiblah and he places the pillar on his left side while supplicating to his Lord for a long time. After stoning the second pillar he stands placing the pillar on his right side while facing the Qiblak and supplicating to his Lord for a long time. This is done on the 11th and 12th day, and also the 13th day for whoever is not in a hurry to leave. In reference to the last stone pillar which is nearest to Makkah, he stones it but he does not stand at it because the Messenger stoned it and he did not stand at it.

Source:
Ash-Shaykh Ibn Baz
Fatawa Islamiyah, Vol. 4 Pages 240-241