Hey there, @HW808.
Thanks for reaching out to us here in the Community.
You'd need to categorize the amount of the contribution to the liability account on the journal entry, check, or whichever you usually use to show you're paying yourself. Typically this setup is automated in our system, so to accomplish this manually, you'd need to reach out to your accountant/bookkeeper to ensure its accounted for properly. If you do not have an accountant or bookkeeper, don't sweat! We can help you find one here in the Community.
In the meantime, I'm including the IRA Deduction Limits from the IRS website: IRA Deduction Limits. Also, here's another handy article to check into: Set up payroll item for retirement benefits (401 K, Simple IRA, etc.).
Please don't hesitate to let me know if you have further questions or concerns. You can always reach out to the Community or me anytime you find you need a helping hand in getting back to business. Take care!