when was the treaty drafted?
4 February
Treaty of Waitangi
Realising that a treaty in English could not be understood, debated or agreed to by Māori, Hobson instructed missionary Henry Williams and his son Edward Marsh Williams, who was more proficient in "Te Reo", the Māori language, to translate the document, and this was done overnight on 4 February. 
what happened during the signing of the treaty of waitangi The Māori and English versions of the treaty were put before a gathering ("hui") of northern chiefs inside a large marquee on the lawn in front of Busby's house at Waitangi.
wiki:18876952
Treaty of Waitangi [SEP] Drafting of the treaty
Realising that a treaty in English could not be understood, debated or agreed to by Māori, Hobson instructed missionary Henry Williams and his son Edward Marsh Williams, who was more proficient in "Te Reo", the Māori language, to translate the document, and this was done overnight on 4 February. The translation of the treaty was reviewed by James Busby, and he proposed the substitution of the word "whakaminenga" for "huihuinga", to describe the "Confederation" or gathering of the chiefs. This no doubt was a reference to the northern confederation of chiefs with whom Hobson preferred to negotiate, who eventually made up the vast majority of signatories to the treaty.