teeder,
Click
HERE and it will take you to the help section. On the left, scroll all the way down to "Configuring and Arena". Under "Arena Settings" you will find what the settings mean and how to manipulate them. From my experience setting up the Special Events Arena, the join command is universal, meaning it works in all arenas the same way.
.join ID --- This will send the message to the ID you choose to join
.accept ID --- This is the command they must enter into the text buffer in order to allow you to join.
.showjoin0 --- Allows for your incoming join requests to be displayed in the text buffer
ie: SYSTEM: REP0MAN wishes to join you. Type .accept ID to allow.showjoin1 --- Allows for your incoming join requests to be displayed as a pop up window. The window will give you a choice to accept or deny. Warning: This pop up window will block your view and can reek havoc on survivability in the heat of the fight

Look through those Configuration settings. There is a ton of cool things you can do.
