Looking for assistance creating language patches

[anonyme]

1) I'm new to alternc

2) I'm trying to learn how to properly modify the language files in

/var/alternc/bureau/locales/en_US

3) Specifically, I want to replace the French instructions at the bottom of  http://alternc.prometheuslabor.com/dom_add.php

4) I can see the files in /var/alternc/bureau/locales/en_US/LC_MESSAGES

5) I'm a little confused, though. I'm not quite sure which file I need to change to generate the binary altern.mo file.

6) Do I change the alternc, the manual.po, or the messages.po file? Can someone please tell me the difference between these files?

Thanks.