Simple CSV Power Query

Hi team,
First time using Power Query.

Background: I am trying to automate one part of a monthly Invoice recharge process. (I will no doubt be asking for help on other parts of this process as well).

I have the workbook and all files in a single folder

I have an Excel Workbook that maps monthly 20k rows of SAP employee data to 60ish Agencies falling under 10 Departments to invoice data. I end up with 10 Department recharge statements listing each Agency's cost split.

1. Each month I rename last month's template for this month.
2. Clear the Employee data tab
3. Copy and paste in the SAP data
4. Clear the Invoice tab
5. Copy and paste the invoice csv data

As my first foray into power query I simply want to use Power Query to eithe/or;

A) Clear the Invoice tab and paste the 'ecsv_' data from from the current folder from cell A1

B) Overwrite the current data with the entire 'ecsv_' sheet so I don't get any spill from the previous month.

My first attempt inserted the data to the left of the existing data, messing up my cell references.