Here there is a list, where you see the channels that you add in your Auto-Join Channels list.
When you choose a channel in the list, you have options to join it, edit it or remove it, from the list.
Then, there's an editbox, where you can type a channel's name and then either add it in your Auto-Join Channel's list or join it.
In this editbox, you will also edit the channel you will select. This option will be enabled if only one channel is selected.
There is also an option for a channel key, which will be used to join the channel, when you execute the /aj command.
With the Join All button, you can join all the channels in your list.
Tip: The # sign will be added automatically, if you won't use it.
You can also find the channels you add, in the Join menus of Status, Channel and Menubar popups.