During Guru Gobind Singh Sahib jee's Guru-ship, Baba Deep Singh along with 24 other Singhs went to Dheer Mal (the grandson of the Sixth Guru) to ask him to return the Kartarpur Bir (the original Aad Granth Sahib jee that Guru Arjan Sahib jee compiled) that he had forcibly taken during the time of Guru Hargobind Sahib jee. Dheer Mal refused and replied, 'If your Guru is the same 'Roop' (form) as the first and fifth Guru Sahibs, then why doesn't he fashion Gurbaani from memory?'Damdami Bir
Guru Gobind Singh Sahib jee stayed Talwandi Sabo (known as Sri Damdama Sahib today) for 9 months and 9 days in 1706 and dictated the entire Aad Granth Sahib jeewith the addition of the Ninth Nanak, Guru Teg Bahadar Sahib jee's revealed Bani (sacred hymns), whilst Bhai Mani Singh jee undertook the task of scribing under Guru Sahib's supervision. Undoubtedly, Guru Sahib got rid of certain unauthorised writings which had crept into some pirated copies and gave the Granth (Scripture) it's final form. As this Bir (Volume) was compiled by Guru Sahib at Sri Damdama Sahib, in Southern Panjab, this final form of the Granth Sahib jee became known as the 'Damdami Bir'.Resting Guru-ship in the Guru Granth-Guru Panth
This Bir was then taken to Sri Hazoor Sahib, NandeR, in 1708 by Guru Gobind Singh jee. In an old text called 'Nanak Chandr Udai Mahaa-kavyan' (ਨਾਨਕ ਚੰਦ੍ਰ ਉਦੈ ਮਹਾਕਵਯੰ) written by Pandit Raaj Sharma, it says that Sikhs asked Guru Gobind Singh Sahib jee Maharaaj before he physically left his body, 'Who is Guru now? To whom should we bow? Whom should we have Darshan of and of whom should we contemplate?' Guru Gobind Singh Jee Mahaaraaj replied that 'the Granth is the Guru. Do it's Darshan. Bow your head before it and do contemplation of it to illuminate the path.'
'Gurū Kīān Sākhīān' describes Guru Gobind Singh Sahib jee conferring Guru-ship to the Sri Guru Granth Sahib jee:
'Guru Jee asked Daya Singh, "Bhai Sikha, go and fetch Sri Granth Jee, we have to endow Guruship." On getting the command, Bhai Daya Singh brought Sri Granth Jee and auspiciously opened and displayed it. One Sikh prepared the parshaad and placed it on a stool nearby. After the supplication, Satguru Jee prepared to pass on Guruship. Guru Sahib took five paise, the coins and a coconut in his hand. Sat on the bedstead and asked Daya Singh, 'Place them in front of Sri Granth Jee' and expounded:Guru Sahib's instruction was:
'With the directive of the Almighty, initiated is the Panth,
All the Sikhs are decreed to acknowledge Granth as Guru,
Believing in Khalsa, epitomises the Guru as corporeal.
Sikhs desirous to achieve me, (may) search in them.'
ਆਤਮਾ ਗੁਰੂ ਗ੍ਰੰਥ ਵਿਚ'The Spirit is in the Guru Granth,
ਸਰੀਰ ਪੰਤ ਵਿਚ
ਪਰਚਾ ਸ਼ਬਦ ਦਾ
ਦੀਦਾਰ ਖਾਲਸੇ ਦਾ
ਓਟ ਅਕਾਲ ਕੀ
The body in the (Khalsa) Panth,
Understand the Shabad,
Seek the glorious sight of the Khalsa,
Take support from the Immortal (God).'"
Additionally there is a nice resource on youtube for anyone looking to learn how to read the Guru Granth Sahib Ji with translations more slowly than other videos. https://www.youtube.com/watch?v=eqIkMmQ4jdc