Question

when Adi Sri Guru Granth Sahib was installed in Sri Harmandir Sahib

Answer 1

On 20 October 1708, Adi Sri Guru Granth Sahib was installed in Sri Harimander Sahib as eternal Guru.

Adi Sri Granth Sahib Ji is also called Guru Granth Sahib or the Adi Granth or Adi Guru Darbar.

On 1 September 1604, Adi Granth was installed for the first time at Harimander Sahib by Guru Arjan Dev Ji.

Adi Granth literally means "the first book" and this Granth (Book) is the Holy Scripture of the Sikhs.