Using File Date in PBI & Calculating the Change based on the File Date selected in 2 slicers

[hammmatk]

So i have been struggling for a few weeks to come up with a solution for this.  Still very new to PBI and the calucations etc.  So let me appologize to start with.

Data File:  This file contains tons of Data and is over 1.2Million rows.  I have a Column (File Date) that keeps the lines seperated and a date table the is connected to a manufactured Data of Completion.  it also has a Qty for the number of widgets that are ordered.

File Date : Qty: Widget: CMAD(Completion Date)

What I am trying to get is the difference/change MoM/QoQ/YoY based off the Changes that occur in the qty;s in the files.  Ideally this is a pretty easy formula, but as i have found likely not so much.  I want this to be able to have two slicers, that select the two file dates for comparison, and the calucaltion utilizes the two slicers to give the results in a table or kpi card etc...  Below is a snipit of the way this looks at present.

Really appreciate any guidance you have as this one has me running circles at the moment and not certain on the correct direction or path.

[lbendlin]

Please provide sample data (with sensitive information removed) that covers your issue or question completely, in a usable format (not as a screenshot). Leave out anything not related to the issue.
https://community.fabric.microsoft.com/t5/Community-Blog/How-to-provide-sample-data-in-the-Power-BI-...
Please show the expected outcome based on the sample data you provided.

https://community.fabric.microsoft.com/t5/Desktop/How-to-Get-Your-Question-Answered-Quickly/m-p/1447...