1st time private lender for commercial real estate. Need advice QUICK!!

[Ginger A.]

I am completely new to REI "NEWBIE" ALL THE WAY, so I have my concerns with a lending opportunity. I asked the developer how is he going to secure the loan so that I am guaranteed the return of my principle? I was told that I will be covered with money from his hard money lender... Not sure how it's all going to work I'm researching now, I just want to know what documents I need to have signed to guarantee my loot back? Is a promissory note enough? It's an opportunity to invest in a commercial property that is being converted to residential space. Any tips will be helpful! I like the developer and think it's a good deal, just want to be smart about it...