What type of expenses?
If you are itemizing your return, you can enter them in the deductions and credits section of TurboTax.
If you have a business, you can enter them in the business section, right after you enter your income. This will be reported on Schedule C.
If you are new to TurboTax or new to taxes, you may want to consider walking through and answering each question instead of jumping around so you do not miss any credits or deductions that you may be eligible for.