Yes, when you have expenses that are shared between your rental property and your home, you must allocate the costs using any reasonable method.
Most taxpayers allocate based on square footage or property value (if known). If the two units in your duplex are identical, you may report half of your shared costs as Rental Expenses on Schedule E.
Costs that apply only to the rental unit should be reported 100% as Rental Expenses.
The easiest way to find Schedule E in TurboTax is to open your return and use the Search box at the top right side of the TurboTax header. Enter "schedule e", hit Enter, then click "jump to schedule e". This will take you directly to the start of this section.
Or go to My Account >> Tools >> Topic Search. Type in "schedule e", then click the topic in the list.
(If you are using the mobile app and don't have My Account or Tools on your screen, try logging into TurboTax from a laptop or desktop browser.)