Find duplicates then update a cell based on those duplicates

Hi,

I'm completely new to excel formulas / VBA / Macros and have been tasked with finding a solution to a daily tedious task i'm now involved in.

I have a daily report sent to me with a list of order numbers.
I need to take those order numbers, find any duplicates from my previous days report and update a few cells to keep track of any delays.

What I want to do is make some sort of VBA / Macro to simplify this.
I want to copy the new days report into a sheet, hit a button and have the VBA find any duplicates then increase a numbers cell by 1.

The order numbers will always be in the A column but the list length will vary each day.
In my head, that sounds fairly simple to do, but I dont know excel so dont know where to begin.

Anybody able to point me in the right direction on making this work?
And what info do you need to be able to advise me how to do it?

Cheers

it would be a lot easier if you uploaded your file so people could look, considering that you are professing that you are brand new.