Entry level powershell assignment, any help would be appreciated.

Question below:

The ABC company is reorganizing its inventory. All of the items in its inventory have an alphanumeric part number like 400CVY409, 400 is the category number, CVY is the inventory code and 409 is the item number in the bin. All of the CVY parts are to be reclassified to BCX. Write a script which will allow the clerk to enter the part number at the console and change the CVY code to BCX. Send the output to a file appending all of the new part numbers. Design your script so that it displays “Enter a part number” until the clerk does not want to enter any more.

I have absolutely no idea how to even go about this.

I was thinking something along the lines of:

Get-Childitem $inventory -include @("*CVY*") Read-Host "Enter a part number" 

But Im pretty sure Im not understanding the question correctly, and that Im completely on the wrong track. That would be under the assumption that $inventory exists, and plus I think I need a loop anyway.