If you are speaking of subtractions to income, TurboTax will automatically populate Maryland's Form 502SU based on your entries.
If there are subtractions from your federal income to derive your Maryland income, this will be reported in different areas of your return, depending on what the subtraction is.
If you give us more information, we can help guide you to the correct place on your return to report the subtraction to income. If you are not speaking about the Maryland 502SU at all, but a different form, then let us know which form you are trying to fill out.
