Text File input:accept file names from prev step

Hi All,
I know this has been discussed before but I still couldn't figure out and how to make it work!

I don't understand what this message really means " Please specify at least one text file sample in the file list. When reading file names from previous steps, this file will not be used during processing."

1. Where should this sample text file be specified?
2. What should it contain?

How to get a file name from previous step?
I have attached Screenshot of the design and the "Text file input" transformation screenshot.

Thanks!PentahoDesignscreenshot.jpgTextFileInputScreenshot.jpg

Attached Images

• PentahoDesignscreenshot.jpg (11.4 KB)
• TextFileInputScreenshot.jpg (22.5 KB)