Paying Back Investors/Private Lenders

[Connor Martin]

As I look into obtaining a first rental property, it is becoming more and more apparent that I will need outside funding to put down a down payment for a conventional loan. 

My question is, if one were to borrow $100k from an investor (whom I know personally), the down payment, how would one financially model paying back the investor in addition to paying off the mortgage? When are private lenders typically paid back? As the investor, would you use the cash flow to pay back an investor over time?

Hopefully that question made sense. Thanks!