Where do I file my IT-245 form

After you have completed the Federal portion of your return, you will move to the State preparation. On the "Take a look at New York credits and taxes" look to the first section "You and Your Family." Next to Active Volunteer Firefighter or Ambulance Worker, click Start. 

TurboTax will prepare an IT-245 based on your entries in this part of the program.

Please note: Full-year New York State residents may claim a credit if they provided volunteer services as a firefighter or ambulance worker for the entire year of 2017 and did not receive a real property tax exemption that relates to your volunteer service.