The first is the age of the minor. If the minor is under the age of 16, you can not sign the contract, otherwise the employer will violate the law. Another is that it is illegal for an employer to arrange a job without training if it is a special job or the work that the institute is engaged in needs training. Regarding resignation, employees should inform the employer three days in advance during the probation period and submit a written resignation application 30 days in advance after the probation period, before they can settle their wages and take a vacation. What you said is not detailed. If you think the unit is illegal, you can apply for labor arbitration.