You need to set up an Application on Zero. Go to https://developer.xero.com/

Click on the My Apps link at the top of the screen

If you are not already logged into Xero, you will now need to login

Now you can click on New App

Enter an Application Name as (ie: CloudHQ-MyCompanyName)

Select Web app

Company or app URL is always:

https://www.cloudhq4.com

Add a callback domain (now called Redirect URI) of

https://portal.cloudposhq.com/modules/Xero/scripts/XeroOAuth2Callback.php

Tick the I have read and agree to the Xero Terms & Conditions and then press the Create App button

You should the have available under App Credentials, a Consumer Key & Consumer Secret - keep these handy as they will be required shortly.