You get a tax refund when your total tax payments are greater than your total tax liability.
Enter your children as dependents in the My Info section of the program. Then enter your W-2 tax data in the Wages & Income section of the program. If eligible, you will receive a child tax credit for the dependents you have claimed.
See this TurboTax support FAQ for the child tax credit - https://ttlc.intuit.com/turbotax-support/en-us/help-article/taxation/child-tax-credit/L2lNhfGDl_US_en_US?uid=mbb2kwze
See this TurboTax support FAQ for the Earned Income Tax Credit - https://ttlc.intuit.com/turbotax-support/en-us/help-article/tax-credits-deductions/qualifications-earned-income-credit-eic-eitc/L7w4BFP32_US_en_US?uid=mbb2mluj
If you are married you need to file a joint return with your spouse in order to get the most child-related credits possible. Your filing choices are to file married filing separately or married filing jointly. If you file separate returns you will not be eligible for earned income credit, or for the childcare credit if you pay someone to take care of your children while you work. You should be eligible for the child tax credit for your children who are under the age of 17.