Where in Turbotax do I calculate rental property depreciation?

The property itself will be entered as an Asset under the Schedule E Rental Income and Expenses section of your return.  

In the Property Profile section, if you checked the box that this is the first year you are renting the property (if it is), then questions about the property itself that are needed to set up the depreciation should be asked automatically.

If this is not the first year you rented the property, then go to the Assets section to enter the depreciation details for the property.  Based on the information you enter, TurboTax will calculate the depreciation amount for you.