Note: The exact steps and appearance varies from phone to phone.
In Settings, under the Accounts tab, tap +Add account.
Select Corporate (might also be called Exchange or Microsoft)
Enter the information in the fields below then hit Manual Setup
Select Exchange for account type (this screen may not appear)
Fill in the fields to match the image below. Make sure in username to enter “nusd-domain\” before your username
Choose what settings you would like for email notifications and what you would like to sync with your device