@anhelarroyo the W-4 is set to mimic the tax return. That means that if your income doesn't yield any tax liability on a tax return, then there is no withholdings on a pay check.
assuming both children are under 17 and you are filing HOH, then if your annual ncome is below $57,000, then your tax liability net of the tax credits for the children is zero. So if your total year income is less than $57,000, there is no need to withhold and your refund / amt due in April will be faily close to zero.
if you are paid 24 times a year and your gross income is $2400 per pay period that is quite close to the $57,000 I note above. Not surprised there is no withholding.
