How to "chmod"?

[makemedie]

Ok, i'm a total newbie in php, all i know is <? is to start and ?> is to end a script.
I need help doing this thing, i got a flash and php chatroom, but it requires me to chmod the file-whatever.txt so that everybody can read, write, and execute it, i mean they can do everything with it. How should i do that?
I mean where should i go and what should i type?
Please help me ASAP.
Thnx a lot. U guys r great!

[Mordecai]

You can either do it through your FTP server, or do it through PHP: chmod("file.txt",777);

The mode is 777 no matter what. When using your FTP program, you'll need to find where chmod is at, then type in 777.