How should I fill out the allocations for form 8379 Injured spouse?

[AndreaG]

Completing part 3 involves allocating income, expenses, deductions, and credits between yourself and your spouse. This is what the IRS uses to determine what amount of the joint refund should be applied to the debt and what amount should be given to the injured spouse. 

You want to allocate these items as if you were both filing a separate return. For example, if you each have W-2s from your jobs, then your W-2 would go on your column in the worksheet and your spouses W-2 would go on their side of the worksheet. If one of you is in school and is eligible to claim an education credit, then that information would go in the column of the spouse who is in school. 

For detailed instructions on how to allocate the items on your tax return, please refer to pages 2-3, under the heading, "part 3" of the IRS form instructions.  https://www.irs.gov/pub/irs-pdf/p970.pdf