Example:

//Instantiating a Workbook object
Workbook workbook = new Workbook();

//Obtaining the reference of the newly added worksheet by passing its sheet index
Worksheet worksheet = workbook.getWorksheets().get(0);

//Add a page break at cell Y30
int Index = worksheet.getHorizontalPageBreaks().add("Y30");

//get the newly added horizontal page break
HorizontalPageBreak hPageBreak = worksheet.getHorizontalPageBreaks().get(Index);