want to sequence files with older ones las on the list

I use my sansa clip to study language lessons and am very pleased with it. I would like to sequence the files on the clip so that the lessons I have learned are at the end of the list of files.  I don’t know how to do this.  I have tried renaming them with file name starting in letters like z but that does not seem to place them at the end of the list.

Any ideas?  

Thank you.