An Excel file (.xls) is also know as a workbook. Within a workbook there are multiple pages, or worksheets. At the bottom of the excel screen you will see the worksheets. They are by default named Sheet1, Sheet2, Sheet3.
In order to add a new worksheet to an existing excel:
1. Head to any of the existing Sheets titles (e.g. Sheet1) and right-click on the title. A contextual menu will appear. Then left-click on
Insert. A menu will appear.
3. You will now have a new worksheet, Sheet4.