You said you were self-employed so I assume you file a Schedule C with your federal return. Your net self-employed income (or loss) is the amount on Line 31 of your Schedule C. Your "California amount" would be the portion of line 31 due to services you rendered to clients based in California.
https://www.irs.gov/pub/irs-pdf/f1040sc.pdf
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
