Structuring a loan with family?

[Tyson Bumgarner]

I'm working hard on building my down payment cash right now, but I can see that if I am to get started sooner rather than later I will need to borrow some money from a relative.

How would one go about structuring a loan like this? Just like a normal bank loan? Figure out a rate, loan amount, and number of payments, put it on paper and call it good? Or is there a different way people do loans from people very close to you? 

I want to come at this relative of mine in the most professional manner with a solid plan so he can see I'm serious and can't trust he will see his money again.