How do you add to a filename?

I'm sure this has been asked before but I searched and couldn't find exactly what I am trying to do which should be quite simple given what I have done and seen done with this awesome program in the past. Simply put, I want to add text to the beginning of a bunch of filenames. Let's say the text is "0000 -" How can I prepend that to a filename? Thank you in advance!

Convert Tag - Filename (ALT+1) and just add the text you want in front of the Format Strings.

For example, the format string is %artist% - %title%, just change it to

000 - %artist% - %title%

Convert>Tag-Tag for _FILENAME
Format string: 0000 - %_filename%