This is a demo tutorial. While there is no step-by-step commentary available (yet), the live demo below is fully functional. Feel free to open it for full source code.
This demo will show how you can add additional worksheets to the data being exported to XLSX format.
For more information on how to modify Excel workbook being exported, please refer to the SheetJS docs.
See the Pen Adding worksheets to Excel export by amCharts team (@amcharts) on CodePen.