[Mailman-Users] more info pls

[Mircea Boldis S]

Hello,

I have install mailman in my website.
I want to get rid of one of one message in my archive.
I see like a solution :
a.. remove $prefix/archives/private/listname 
a.. edit $prefix/archives/private/listname.mbox/listname.mbox [optional] 
a.. run $prefix/bin/arch listname 

Ok, sounds good, but I have no idea from where to start.
Are these commands, if so where to type them ? Are from menu's ? ... 
Please help, because I don't want to see that message in my archive anymore, please.

Thank you in advance.
Mircea