Once there, you will find that you can launch a bot in one of three ways, the first is with the keyword -pick and do note the - in front the word. This will launch the client in pick mode where you can select which alt you want to use for your session. It's a handy test feature when you're designing a bot for someone else, or when you want to modify an existing bot that is currently connected with a different alt.
The other two modes is where you can enter the username, password, colors, and description directly into the appropriate spaces, or use the Load INI File button to have the program load them for you. Once you have this information loaded into the bot, you can edit it as you wish, and the bot will remember your edits.
The upside of this is that if you pass the bot along, the alt information is embedded into the botscript, so whomever gets the bot will have the information needed to start the bot. The downside of this is the same thing, you're passing along a username and password to the alt being used.
Fortunately, there's a third way, you can just point the bot to use a specific INI file on your computer and the program will launch that file as the parameter for the client, the client uses that alt to connect to the server, and the bot loads the relevant data into the internal variables when the client logs in. The upside of this is that when you pass the bot along, you're not revealing sensitive information, like your password. Downside is that whomever gets the bot needs to have a file in the exact same place as yours. Or at least a file named exactly as the one you used.
Which almost works pretty good, there is a single catch or two involved. First is that this is dependant on the INI file existing in the default location which the client looks in for the ini file, if it fails to find the file, it will start in "Create A Character" mode. This will also happen if you have selected an INI file which is not in the default location for the client to look, even though the file exists on your computer, what the bot passes to the client is just the filename. To work around this, you will need to open the main configuration of the bot and check "Use long paths for character selection on client launch" setting. This will start the bot with the full path to the INI file to use for the alt.
This will also fail if the client fails to find the INI file in that location as well, but helps you out in that you can keep your main alt used for botting in a different folder and not have to worry much about accidentially starting a furcadia session with it. Disconnecting the bot of course.
Getting Started 
Oh hey, what's this? You need to set a name into the bot? Well it's actually fairly easy to do, all you have to do is select Bot Settings under the Bot menu and you get this dialog. Once here, there's this neat button you can press to Edit Alt Info and it will bring up the Alt Selector dialog.
Once you've used the the Use INI File button, or you've got a bot in which there is a file already set and you just need to figure out where this INI file is, you can click in the Username part of the dialog, and use the arrow keys to scroll about and figure out what's going on. You can also directly enter a filename here, but the Use INI File button does make things a bit easier.
Once you've gotten this all setup, the Bot Specific settings will display the username, and password if you go the route of embedding the alt info into the bot. If it's a file, only the filename is shown, not the path.