If you are claimed as a dependent on someone else's return, you cannot claim dependents on your own return. If you have inadvertently answered you are being claimed as a dependent on another taxpayer's return, your dependents will not appear in Box 6c on page 1 of Form 1040.
To correct this, if necessary:
Answering No to the question Can you be claimed as a dependent on someone else's return, such as your parent's return? will result in any dependents already in the return now being listed in Box 6c of IRS Form 1040.