Make sure you have service or that you are connected to WiFi before starting. Go to Settings. Mail, Contacts, Calendar. Add Account. Exchange. Your Email is email@example.com
. Username is first_last. Enter your password. Tap Next and it will start the verification process. This step will take 30-90 seconds. Tap Next and you should get all green check marks. Your email, calendar and contacts will now start to sync with your phone. This video does a great job of describing the process.