You need to enter the world of VBA. From Excel, open the VBA development window by pressing ALT-F11. On the left is a a hierarchy that lists open Excel files, and under each Excel file it lists VBA modules under a folder called "Microsoft Excel Objects". Each of the objects listed underneath is a module which can contain code. Every Excel workbook by default has one module for each worksheet (Sheet1, Sheet2, etc.), plus one module for ThisWorkbook. You can also add new modules that get default names like Module1, Module2, etc.

Find your file in that list, and look at the module named for the worksheet named July, which is the only sheet in your book. Double click on it and you can see the code in the window on the right. It's a bit of a leap to go from not knowing VBA or programming to understanding how all this works. There are many resources available paid and free for learning about VBA. I don't want to try to teach a course in this thread but I can answer specific questions.