Welcome to Mediumwave DX(MWDX) chat!
Once the software has been installed, start it. It will ask you to choose a server for chat. You'll want the Starchat server. It doesn't matter which Starchat server you choose, but it's best to choose the one that's located closest to you. A list of Starchat servers can be found here: http://www.starchat.net/servers.htm or at http://www.mirc.com/.
You will also need to choose a nickname for chatting. Your nick can be up to 8 characters long. There's no special formula for the name. Choose a name that best suits you. The name doesn't have to be the same from one session to the next. You can change the nickname on-line, if you prefer.
Once you're logged onto the chat server, (which may take a few minutes; it can be a slow process depending on the number of users logged in), the system will log you on and ask which channel you want to go to. You don't need to get an entire list of all available channels, unless you want one, (there's over 20,000 channels!) . The channel you will be using for BCB chat is #mwdx. Enter this when asked - and no, it's not case sensitive.
Have more questions about chatting? If you're on-line, go to #mwdx or #swl on Starchat and ask Bill Harms, Barry McLarnon or David Ross.