Create headers in workbook based on cell references.

I am new to VBA & macros, so I've had little success customizing other answers to fit my needs. I'll also appreciate any answers including a simple explanation of how to implement.

My issue:
I have a workbook I use for listing information for construction projects. I would like to fill in the left, center, & right headers on each sheet, to reference cell info from the first sheet. Example: when I enter the Project Name in Sheet1, Cell C3 - I would like to see that Project Name appear in the center header on all sheets in the workbook.

Do I use VBA? Macros? (not completely sure what they are, really) I'd like to use this solution on more than one workbook, right now I select all sheets and change the headers in one to reflect to all, but sometimes I change the Project information and forget to update all the headers, it gets a little messy and I'm looking for a better method.

My worksheets are renamed - the first sheet (which has the cells I'd like to reference) is titled "P1A.Details"
The Cells I'd like to reference are all merged - the Project Name cell is actually C3:I3
I've attached the excel file.

This is my first post, looking forward to finding a solution to my problem and any advice on using this forum. Thanks in advance!