2020 CA DE-4 form Worksheet C Item 1: only my income or mine plus my spouses?

I am filing this form and per its suggestion, want to submit only one for my wife (who works) and myself. For Item 1, should I only include my gross income or both of us?

If the income of both of us is needed, does it mean for line 13, I have to combine how much is deducted from the pay stub of both of us?

 

If this is just my income, then I am more confused. It seems that unlike W4, this form does not care about our joint income.