rental property - multi-unit

I have a property that is classified as duplex. I selected the multi-unit option, and it is clear how to report the rental income, but I am not clear about how to enter the expenses such as property taxes and mortgage interest. Should I enter only the portion related to the rental half of the duplex, or should I enter the total amounts and let TurboTax divide them accordingly? If I do need to enter just the rental portion of the expenses, where do I report the property tax and mortgage interest for the half that I live in?

Also, in the case of a fourplex, how does TurboTax know how to apply expenses if I am renting out 75% of the property to others? How do I specify that under the multi-unit property option?