Download XCHAT 2.8.6-2 (Just click, or right click and save target/link as ....)
Click on the downloaded file to install. Once it is installed, start it and you will see the network list like below:
Put in nick name (for example: fool), second choice (fool_ or fool2 or whatever), third choice (fool__ or fool3...), user name (fool) and real name (fool's secret admirer ;-) )
Click Add to add a network, name it davang
Click Edit, you'll see a new window for editing davang network
Click Edit to change the line "newserver/6667" to "irc.davang.org/6667"
choose "Use global user information" and "Auto connect to this network at startup"
put in "Favorite channels" the rooms you want to join by default on startup(#davang, #trivia, #vietchat ...) and the nickserv password to identify your registered nick if neccessary.
Final result will look similar to this screenshot below: