Which kind of 1098? A 1098 from a lender for mortgage interest? A 1098T for college tuition? A 1098E for student loan interest?
The 1098, 1098-E and 1098-T are only informational documents. The numbers on them are not required to be entered onto your tax return.
What is it your are trying to accomplish; mortgage interest deduction? Student loan interest deduction? Claim the tuition credit on the parent's return? Claim the tuition credit on the student's return? Report taxable scholarship?
For Form 1098, here is how to navigate and enter the amounts:
As @Hal_Al mentions, there are a couple other 1098 forms, so please clarify if you are looking for instructions for one of the other forms.