Weekly Excel Report Automation

I keep one master report in Excel and every week I receive three supporting reports, also in Excel. I need a reusable template or automated routine that will:

• Pull the latest data from those three supporting workbooks.
• Append any new entries and update any existing rows in the master (no need to handle deletions).
• Standardise every date field to one consistent format.

Beyond that logic, there are a few simple addition/subtraction calculations inside the sheet that must continue to work once the data refreshes.

I am happy for you to tackle this with Power Query, VBA, formulas, or whichever Excel-native method you feel delivers a one-click refresh. When you are done, I will need:

1. The completed template/master file wired to accept the three source files splitted into two reports maintained based on site code column
2. Clear, concise instructions (written or short screen-share recording) so I can run the weekly update myself without tweaking code.

Accuracy in the merge rules for new and updated records and spotless date formatting are the key acceptance criteria.