Click on Federal from the menu to the left (in black)

Choose Income & Expenses from the menu at the top.

Choose the First category for Job (W-2) and choose Edit/Add

Scroll down and choose "Add a W-2 for (Your Name)"

This will get you back to the screen where you can add your 2nd or subsequent W-2's.

Did you already file the first W2?  Then you need to mail in an Amended return to add it.  Post back for more info and do not enter it yet.