How to structure a private loan

[Robert Graham]

I have $40k for a down payment on a duplex. I’m already pre approved. After closing I want to borrow $20k from my relative to replenish my bank account so I can have buying power. How do I structure the loan at 10% with a 5yr ballon (or better terms if you have ideas)? How do I explain the repayment to her so she can see the benefit? She’s told me that she’s willing to help financially.