An export is just a different view of your data like a Week View or Month View except it is normally used to get data out and into a file for opening in some other tools like Excel.
From the Views
menu you can choose Run a report
where you can set a filter to choose the data you want and then choose report sample 5 or 6 to get this data in a CSV file which can be opened in Excel and other spreadsheet tools.
Using the Report Editor
you can fully customise the columns of data included in the export reports. For more details on creating custom reports see this topic... https://www.scheduleit.com/faq/10807/report-editing-and-customizing-or-create-new-reports