To Add API integration please log into the backend system and navigate to 

System Management > Organizations.

Click "Organizations"

Click "Edit Icon" next to the Organization name you want add an API Integration.

Please Click the "API Settings" tab.

Please select from the "API Selected" drop down list the integration of your choice.

Please then Fill out the "API URL" & "API Key" that is provided by your Host.

Please create a username & password and click the "Save" button.