Paying interest to my private lender

[Alexandra Scardo]

I have a person interested in lending me money for a flip but she’s never lended money and I have never borrowed from a private lender. I know this is basics but I really don’t know.
So let’s say I borrow $10,000 for 5 months at 10% . Just one payment at the end of the 5 months. How much am I paying her? Is it 11k or 15k? Does the 10% interest accrue monthly?  Thank you so much for helping me learn.