@Pedro Urena,
Just like @Jaysen Medhurst said, you can structure this deal however you want.
Here are my suggestions on putting it together.
1) Protect your friend. They are doing you a huge service. Your #1 priority should be securing their investment.
2) Get all your docs in order. At the very last, you'll need a promissory note, a mortgage, & a personal guaranty.
3) Prepay Insurance on the property for 1 year and name your friend as the lender.
4) Use a reputable / reliable / recommended title company for closing (they will record the mortgage for you with the county). They will also provide a loan policy for your friend.
As far as the terms go...
Private Money Loans float anywhere from as low as 0 points and 8% to 2 points and 12%. If this is your first deal, I'd model 2 points and 12% and make sure it still works.
I'd say a maturity date of 9 months should suffice.
Depends on the deal, but I wouldn't want to be in it for more than 65-70% LTV as the lender.
So I'd probably require you to put 20% down and then work out a draw schedule for rehab.
Hope this is enough to get you started.
If you want to talk more about this, just DM me. Gluck!