Help Set up deal for my sisters house

[Shelly Rike Mitchell]

My sister needs to move now for work and is asking me to buy her house. I’m not sure how to set the deal up. She has a loan at 4% interest and owes $75k she has been paying for 10 years. She bought house for $150k and wants $190k. It’s probably worth about $210k. She is willing to take a 10% down payment and have me take over paying the loan. But not sure where to go from there. Help appreciated.