The money you hear about people getting for just filing a tax return claiming kids requires you to have some earned income (wages or self employment). Without earned income, you are not eligible for the "refundable" Earned Income Credit or Additional Child Tax Credit.
You only get a refund if you paid more in taxes throughout the year than you were legally responsible for. If you paid the right amount, you'd get no refund, and if you paid too little, you would owe.
On W-2 Form Line 2 you can see your Federal withheld for the year.
On 1040 TAX TABLES (2017) you can see how much taxes you have to pay on your Federal income.