EDIT: Just realized I read that wrong and thought the poster was the seller. 5% rate and 5% down is a sweet deal, take that if you can get it!
First, if you resell the note, most investors will want a 10%+ return. So if you create it with a 5% rate you would need to take a large haircut to sell it. Most seller finance notes have interest rates in the 9-10%+ range.
Also, 5% down is very little skin in the game for the borrower. I recommend at least 10%, and obviously, something closer to 20% is a lot better.
Is the borrower going to live in the home, or is this an investment property? If it will be owner-occupied, there are a number of compliance issues to ensure you address (Dodd-Frank, etc).
An attorney or title company can draft the legal docs. If you DM me, I can send suggestions.
Yes, you'll want to record the docs after you execute the transaction.
Also, don't self-service the loan. You'll want to hire a licensed loan servicer to take care of that for you (Provident, Madison, FCI, etc). You can write into the agreement that the borrower pays the servicing fee.