If you do not have an infrastructure to receive and process notifications, you can use the extract data by polling approach.
Generate access token using client credential authentication as described in Getting Started.
Invoke the get data extracts event service to learn which user in a given time period had the data update events.
Invoke the get user data service to retrieve the information receiving during polling. Note: The transactions entity in the get user data response is paginated. If there are more than 500 transaction updates, only a maximum of 500 records will be returned in the first response. To retrieve the next set of transaction records, use the URL provided in the links header for the next attribute. You can repeat the process to retrieve all the records. There will not be next when there are no more records to be retrieved. This feature is not available for customers who have implemented this API before July 2018. Please contact Customer Service if you need any help.
Extract Data by Polling - API Flow