You might need to be more specific about what deduction you can't find as a Form 1098 can be used in a few different deductions. But, since you said itemized, I am going to assume you mean mortgage interest.
The most direct method to get to this section is by using the search feature. But, make sure you are signed into your account and you click the button Take Me to My Return before you try to search. Otherwise, you will not get the right screens. Use the search function (magnifying glass in the top right corner) and search for "1098" and this will bring you right to the mortgage interest deduction section.
Alternatively, you can always use the interview and select the Federal tab on left-hand side of your screen -> then select Deductions and Credits -> click show all tax breaks -> click Your Home -> select Mortgage Interest (and/or Property Tax section if you also need that)
