I always use a Properties shape to set File Name and Folder for a Disk Write connector. That doesn't seem to work for a Disk Read connector, it seems I must use parameters. Why? Or, did I do something wrong?
For the disk READ, you would set these values in the "parameters" tab on the connector shape itself. You'll be able to set the appropriate values once you have added a Disk "Get" operation to the connector.
Below screenshot on disk connector can answer for your debug
Retrieving data ...