how to modify and add values to template SalesReceiptPrintTemplateJPOS.ftl from java

Dear experts:

I would like to know in what way I can add data to the print template from my Java backend, since I have data that I would like to add to the template.

Currently from java I create my own PrintJobBuilder class and I add fields with SelectableDataStructure.

But I do not know in what way I can from my JAVA backend fill data to those fields. I was seeing something with @ListenToExit (exitName = "BasePrintJobBuilder.mergeTemplateWithData") but I still do not see it clearly.

Does anyone know how to do this?

Thanks!

Jose.