Power Query: dynamic source, use parameters?

Hi all

I'm trying to make my Power Queries more flexible. 

Starting position: I have three queries that have two xlsx files (SAP exports) as a base (connections only). The two files show Equipment data from different dates, which are compared using the queries. They show new equipments, removed equipments, and changes.

The files are named by date, so 01/08/2024, 01/09/2024 etc. And are all in the same folder.

My goal: I want the end user to be able to pick any two SAP exports within Excel and the queries to update accordingly. They should not use Power Query Editor to change the query source.

I tried parameters but failed when connecting it to the dedicated cell in Excel.

What are the steps using parameters? Or are there alternative solutions?

Thanks from a beginner!