Investors & landlords

Hi,  not sure if this is a bug in the software itself or I made data entry mistake.  I sold my property  with 10years installment payment plan from the buyer.  I actually paid the capital gain already at the same year the property is sold. But, why TurboTax is putting the yearly principal payment in the capital gain box for me, not in the ordinary interest box.  I simply followed the steps provided, but this steps lead me to the enter the data in the wrong place. Please advise. I needed to fix it because I do not want to overpay since I already paid the capital gain at year 1.