Pagdi system house

I am in the process of purchasing a new house in pagdi system. I am buying it directly from landlords Son, so he said he will attach power of Attorner from his Dad to make the sale I wanted to know, what all papers should i create for rightful transfer of the house. he said something about 3 papers, Sale Deed, tenancy Right, Power of Attorney Kindly advise as to how many and which papers should i create