Enter your first W-2. After your first W-2 is entered, it will be displayed on the Add / Edit / Delete Wages (Form W-2) screen.
On that screen, you'll be asked if you need to enter any more W-2s for wages and salaries. Click Add a W-2, and you can enter another W-2. Repeat the process until you have entered all of your W-2s.
Remember to only enter a single W-2 for each employer. A W-2 will have a federal copy, a state copy, and a copy for your records. You should only enter the same W-2 once, not multiple times.