I am claiming my son Brandon. He worked during the 2016 year. How do I add his W2?

You don't enter his W-2 on your tax return. If he made more than $6300, he must file his own return. If he made less but had federal income tax withheld, he can file a return to get a refund.

If he files a return, make sure he checks the box that he can be claimed by someone else.