To apply the patch:

- Copy a Japanese ROM file of Rockman ZX Advent (CRC32: 89C919BC) in the patch folder (where this !README!.txt file is);
- Rename your ROM "zxa.nds";
- Run "Patch ZX Advent.bat";
- Done! You will now see a file named "zxa_undub.nds" next to your original file. This is the undubbed ROM, you can now play it.

Good luck!

If you're on an operating system different from Windows, I'm afraind I can't provide an instruction for you.
You'll have to google how to apply VCDIFF patches using xdelta3 on your own. It's definitely possible.