You should see a list of options appear in the right sidebar. If you want to add Gmail account on the app, Hit the Windows + I key from the app screen.
Now your Outlook is setup with the Windows 8 Mail app. Now it will ask you to Login with your Microsoft Outlook account, sign-in here and let the application sync your Outlook mail or Windows Live Mail. If you have the Microsoft account, then go to the Windows 8 start Screen and click on the Windows Mail app tile from the screen. So today i will show you how you can setup your email account in Windows 8 using your regular email address such as Gmail, Hotmail or any other email address you own. To use this windows 8 mail feature all you need Hotmail, Live or Outlook account.