Amortizing start-up expenses

This is my first time using TurboTax Business 2020 to file my business tax returns.  I need to enter startup costs that were on my tax return last year and will be amortized over 180 months.  If I enter them as a deduction, TurboTax doesn't understand they were incurred last year and some of the expense has been deducted.  I'm not filling out the Balance Sheet because I am a smaller business and it's not required.  Where do I enter the start up costs so it is accurately tracked and deducted?