On a rental property, i cant seem to find out where to include my Mortgage expense, or should i only show my profit in the "rental income" section

In the Rental Income & Expense section you will enter the interest expense in the area for mortgage interest.  

The principal payments on your mortgage are not a deductible expense for your rental income.  Instead, you will take depreciation expense on your property.  

To set this expense up, you will enter information about the property in the section titled Assets.  Because this is a bit unfamiliar for most people, it can be a bit tricky the first time you go through these steps, so be sure to make use of the blue links throughout the section that offer additional insight, help, and guidance as you navigate through the program.  

Of course, feel free to post additional questions here for help as well!