Make sure you have a different account and user ID for your dependent. Do not use the same one you used for your own return or you will overwrite your return and lose it forever.
If your dependent has a W-2 for his after-school job, summer job, etc. you do not include the information on your own return. You can still claim your child as a dependent on your own return. He/she can file his own return for a refund of some of his withheld wages (he won’t get back anything for Social Security or Medicare), but MUST indicate on it that he can be claimed as a dependent on someone else’s return. (Supervise this closely or prepare it for him!)
If your dependent’s earnings were over $400 and were reported on a 1099Misc then he must file a return and pay self-employment tax for Social Security and Medicare. You may want to use this version of TT for that:
https://ttlc.intuit.com/questions/1900583-what-is-turbotax-free-file-program