You must be an Administrator within Gearbox and have a Xero account created before proceeding. 1. Click on the User Icon (1) then click on Settings (2).
Xero Integration - User Icon Settings
2. On the left-hand side of your screen scroll down and click on Integrations (3).
Xero Integration - Integration
3. Scroll down until you find Xero, click on Connect to Xero (4) (pop-ups must be enabled in your browser to continue).
Xero Integration - Connect to Xero
4. A login pop up will appear, enter your Xero login details.
5. Xero will then prompt you to enable two-step authentication for security purposes. Click Set up two-step authentication button to proceed.
6. The below example is using the Google Authenticator app. For further information and options click here to view Xero’s two-step authentication guide. Once you have your authenticator app connected to Xero click Continue. 
7. In the next screen enter the code from your authentication app and click Continue.