Go to Settings > Integrations and Keys, click New key, and search for Zendesk. Select the item and click Continue.
In the Configure Zendesk dialog, specify a key name and your AWS region, and click Save.
In the Integrations list, where your key is now included, click Authenticate..
Enter the user name and password as described below.
Now that you've configured your integration, add one or more of the integration's actions to an automation, test the automation, and then add the automation to an incident type.