To create your data flow please first register at the Microsoft Flow portal. Next go to MyFlows to create your own one. You will find the pre-defined SharePoint Flows in the list like this:
Fig.: Find pre-defined Flows for data changes in SharePoint in the Flow actions list.
Next connect Flow to a specific SharePoint site and list as follows. The list or library will act as some kind of intermediate storage to push your specific data into the Microsoft Flow. Create the list or library and also additional columns if required.
Fig.: Setup your SharePoint list or library as a Flow data source.
Once your list is connected you can add any supported Flow Action or Flow Condition on data changes in the SharePoint list. Currently the following systems are supported with Microsoft Flow.
Fig.: Microsoft Flow currently supported systems.
Please first verify your newly created Flow by applying manual data changes within your SharePoint list or library. If your specific Flow runs as expected, go the next step and connect the SharePoint list to your backend system as required: