Basically missing something

Greetings Majordomo users.

I am trying to configure Majordomo on a hosted site and I seem to be  
missing some very elementary syntax information. Since Majordomo is  
on a hosted site, I don't have write access to the configuration  
files. I was under the impression that one could do this  
configuration by email but I can't get the syntax correct.

What I want to do for several lists is to make them "announcement  
only" as well as edit the footer and limit who access.

I have figured out how to subcribe/unsubscribe myself and others by  
using the following single-line command in the body of the message  
sent to majordomo@mydomian.

approve password subscribe my-list jdoe@domain

Other user commands are available by send the single command "help"  
to majordomo.

I have failed to figure out how to send configuration commands. The  
syntax must be very simple to those who know. I have tried--in  
various combinations of spaces and line breaks and order, the  
following to change the subject prefix for the list. Naturally, it  
was sent to majordomo@mydomain

approve password my-list subject_prefix=[$LIST]

I get back an error message like this:

 >>>> approve password my-list
**** approve: unknown list ''.
 >>>> subject_prefix = [$LIST]
**** Command 'subject_prefix' not recognized.
 >>>>

This doesn't seem to recognize my-list nor the attempted command to  
set the subject prefix. It should be simple, yes? Just _what_ is the  
proper syntax for sending such commands to configure majordomo lists?

Thank you,
Bucky