If the sale resulted in a loss, you cannot use the installment sale method; you have to deduct the loss in the tax year of sale. You can do so in TurboTax by starting in the Rental Properties and Royalties section of the program and note that you will need to enter information relating to the rental property itself.
Also, note that the installment contract has to provide for adequate stated interest and, if it does not, the IRS may recharacterize part of the stated principal amount of the contract as interest (even if you have a loss). Consequently, you will have to report interest income on your return.
See https://www.irs.gov/publications/p537#en_US_2018_publink1000221598
I would recommend that you seek professional tax guidance on this matter.
