Ensure that you are in the stream that you wish to export data from.
Select the drop down menu which is located on the top right hand side of your dashboard (the ellipsis).
Then as below, select "Export Stream".
Select csv or jsn and then download it.
This export will remain available for two weeks from creation and can downloaded at any point in that time.(If you want to download it again, go to REPORTS on the top menu bar, select downloads and then click on the export that you would like to download again)