Question

How many members were present at the first proceeding of the constituent assembly of india. Also the day and place where it met

Answer 1

389 members. New Delhi on 9 December, 1946 in the Constitution Hall which is now known as the Central Hall of Parliament House

Answer 2

292 members from legislature, 93 members from Princely states and 4 members from Chief Commissioners' Provinces; the total membership of the Assembly thus was to be 389. were present at the first proceeding of the constituent assembly of India. 

They met on 9 December 1946 in  in the Constitution Hall, New Delhi.. :)

The First Day's proceedings ended after all the 207 members present submitted their credentials and signed the Register. On 13 December, 1946, Pandit Jawaharlal Nehru moved the Objectives Resolution