Wrap Around Mortgage

[Summit Aryal]

Hi everyone, this is my first post here. It's regarding Seller Financing.

I want to purchase a house in Houston that is owned by my cousin. As the interest rate that I'm getting is over 5.875% nowadays I was thinking about doing seller financing with him. He is willing to do 4% interest on the house after I pay him 20% down payment. We have agreed on a price of $300k for the house (which is fair for this house). However, this house is not paid off. Which is why I was thinking about doing a wrap-around mortgage on it. He has never done seller financing before. This is going to be my first house purchase ever, so I do not really know how to proceed. Here are the questions I have - 

1) Where do I look for the due-on-sale clause? 

2) When I do Wrap-around mortgage, is the title going to be transferred to my name? Is he still going to be on the title?

3) How do I proceed with this deal? Who should I talk to to get this deal going?

Any input is appreciated. Thank you!