If they each have income, then in the current income section, use their pay stubs to calculate current income. Formula is gross X number of pay periods in a full year. 1k a week is 52k a year. Enter properly and the form will total it. Tax return numbers are the same on both forms.
Just to clarify, there is no way to hide one spouse's income, and for Consular Processing, trying to do without the joint sponsor's spouse's I-864a is likely to delay your process. Best practice to include it. Follow the excellent instructions for doing so.