Bismihi Ta'ala

There are two main pillars of Hajj: 1) Stopping at the plains of Arafah on the 9th of Dhul-Hijjah between Noon and Sunset for one moment. 2) Tawaaf-e-Ziyaarat, which is the Tawaaf on the 10th of Dhul-Hijjah after pelting, slaughtering and shaving or trimming.

There are certain Waajibaat: 1) Donning the Ihraam from Meeqat 2) To stay in Arafah for the full period between Noon and Sunset on the 9th of Dhul-Hijjah
3) To stay in Muzdalifah between the Subh Sadiq and sunrise of the 10th of Dhul-Hijjah 4) To pelt the Shaytaans 5) Slaughtering the animal if your Hajj is Qiraan or Tamattu' 6) Shaving the hear etc

And Allah knows best.