Thanks for the add-on name. Which operating system does your friend's box use? Ah, not to worry. Some of the online documentation indicates it isn't available for Android, but that may be out of date?
Watch the video here -
He uses the URL
http://xty.me/xbmclivetv in the video, but if you read the little speech bubble type thing, you'll see this URL has been updated to
http://xty.me/vdubt25 , which is what should be in your system already.
OK, I'm still struggling with this one. Windows 7 64-bit with Gotham, I've had it working no problem. On Android, XBMC 12.4 doesn't work (the video guy does mention this, but I thought it was worth a shot.) I had no joy with Gotham 13.1 on an AC8350 X7, I'll try 13.something else next, and see if I can find 12.3 on one of my devices.
Short version? Try copying the steps taken in the video. If you're using the newer Confluence Customizable Mod skin, then you'll need a slightly different menu - click around the same settings area the video shows, and you'll come across it, and I think the Live Streams area in the home screen has IPTV shortcut if you scroll to the right.
I'll post with more info I succeed with Android.
[edit]
Posted before seeing johnfirewall's response. The playlist you need to enter is in that YouTube video, and if you visit the page on YouTube's site, someone mentions a partial EPG pack URL to enter as well. Good luck.
Go to XBMC>System>Add-ons>Search>type in Simple and then start the search. If you see PVR Clients - PVR IPTV Simple Client listed, click on it (you'll need to scroll down a little to find the entry). Click on enable, and wait whilst XBMC reconfigures.