If instead of using the provided template file you want build on an existing workbook of yours, you need to follow these steps to embed the functions into the workbook:
- Open the VBA macro editor (to find the VBA editor in Excel 2007, check Options: Popular: Show Developer tab in the Ribbon. In Excel 2003, you can open the ditor from Tools: Macro: Visual Basic Editor)
- In the editor, select Insert: Module
- Copy all the VBA code from the template file into your new module
- The functions can now be used in the workbook. If they don't work, check that your Excel security settings allow the execution of macros. If they don't, change the setting and restrart Excel.
- In Google Sheets, in your existing spreadsheet, open the menu bar and go to Tools: Script Editor: Blank project
- Copy all the script code in the template into the Script Editor of the uploaded spreadsheet
- In the Script Editor, press Save and return to the spreadsheet