You want to use Form 8606:
https://ttlc.intuit.com/community/accessing/help/where-do-i-find-form-8606/00/25713
"not sure how to factor in the contributions here to determine how much tax to pay."
Make sure to understand why this might be completely taxable. There are three types of Contributions in a Traditional IRA, and you might have only one type, two types, or all three types:
Your own, Pre-tax
Your own, Post-tax <== this is called Your Basis
Your employer's match, Pre-tax
plus any growth or earnings, which would be Pre-tax
If you have no Basis, then everything has gone in tax-deferred. Everything that comes out will be taxed as ordinary income, because it has never been subject to taxes. Done.
Or;
You have Basis (put in funds post-tax), then when you took/take funds, that amount is a part of all funds in all tax-sheltered IRA accounts. That is the % or $ taxable. Form 8606 will help you track the changing Basis.
