FSBO Land Sale - First Time Seller - Need some help

[Jimmy Nguyen]

I am selling a piece of vacant land in an urban area that can be used to build a single family home.  I got an offer on the property, but the buyer said they could do 15% down and pay off the rest in 8 months.  I am not really clear how that works out.  I'm guessing they need to build the house on the land and then use the money from the profits of the sale to then pay me the rest.  Is this standard practice?  Is there any questions I should be asking like should I get any interest for those 8 months.  Thanks for any help you can give.