Hello my name is emiley

hi. I started a new job last month, on the new w-4 I am not married or do not have 2 jobs. So I skipped the 1st part and filled out the rest, I am filing H-O-H and claiming 2 dependents. But no regular federal tax has been withheld. Only fed ss and fed Medicare. I asked my employer about it they said I need to see a tax expert and find out if I'm filing right. What am I doing wrong ?