The Administrative immortal account is the one that is specified in etc/server.cfg:
immortal_name = ~Papi~
You should change this to the name you will register on the MUD to be the Wizard of Wizards, the God of Gods. Once you've saved that and re-run the MUD, you will need to create the character by logging into the MUD. Upon the second login, you'll have administrative power. It is recommended that you NOT use the overall admin character, but instead create another character for day to day administrative duties. With great power comes great responsibility, but with great power come grave mistakes. :)
To set the wizarding level of other character, use the command: Advance <char> admin <level>
For ultimate power, you may set the level to 255. You will want to set the Wizarding level lower on later logins to ensure you don't mistakenly fire off the nukes that you'll have with all of that power.
(Update command/level chart here later?)
Who's in power
You'll want everyone to know who is in power - The 'wizlist' command draws from a configuration file in ../etc/strings/wizlist. Now that Diku is web-based, you'll want newlines to be paragraphs or have HTML breaks, so include markup in the file.