I am using AWS data-pipeline to export a DDB table, but when I activate I get an error:

`Web service limit exceeded: Exceeded number of concurrent executions. Please set the field &#39;maxActiveInstances&#39; to a higher value in your pipeline or wait for the currenly running executions to complete before trying again (Service: DataPipeline; Status Code: 400; Error Code: InvalidRequestException; Request ID: efbf9847-49fb-11e8-abef-1da37c3550b5)`

How do I set this `maxActiveInstances` property using the AWS UI?