How do I structure terms with a private money lender?

[Samuel Bell]

I'm planning on purchasing an investment property in the range of 30K-50K, instead of using my capital looking to borrow from a private money lender. This private money lender is an investor with many properties and is sitting on some cash, he is willing to fund me to grow my portfolio. I'm new to private money and I have no idea what the terms would be i.e. rate, how long? I was thinking of maybe 5 years but the positive cash flow would be around $400/month, so to pay off the loan in 5 years I would have negative cash flow. Negative cash flow is ok because my thinking is the property would be paid for in 5 years, the business has reserves that can take the hit, the private money lender would get his money back in a short period, and I would be able to write off the tax depreciation and expenses which will help the whole of the business. Is my thinking wrong? What am I missing? How do do I legally protect myself i.e. a note? How do I protect the lender i.e with his money i.e.a lien? Any suggestions would be greatly appreciated. Thanks