How do I formalize this private loan

[Allison Karrels]

I have an offer from a friend of my father to loan me $25,000 at 5% over 5 years.  The money will be used as a down payment on a duplex I am looking to purchase.  I am financing the remaining 75% with a traditional mortgage company. 

How would you make this a formal loan - Do you just write up a simple promissory note and attach a loan amortization table to it showing what the payments will be over the 5 years.  Perhaps get the promissory note notarized? Is there anything I need to formally file against the property?

When I make the monthly payments should I send a monthly statement or end of year statement - something to prove I have been making the payments?

Thank you for any guidance on this - very new to taking on any private money.

Allison