How to use Excel Download Button with multiple Worksheets

Dear app builders,

is there a way of getting data from a datasource into a second worksheet? All I have tried leads to the conclusion that you can only hard code information there. I also tried to put information which is stored in a variable in there but this also doesn’t seem to work.

So what do I need to do to get data into the section “additionalSheets” either via datasource or variable?

All help very appreciated!