First Make sure you are patched up to 1.23
http://us.blizzard.com/support/article.xml?articleId=21220Once signed in to Garena, goto the settings page. For Warcraft III you will need to browse to war3.exe in the install directory.
Go ahead and do that for both TFT & TFT:RPG.
Make sure your firewall is cool with Garena.
Then go to War3 RPG room.
Select one of the USA DotA rooms that has a ton of people.
Hit the start game button on the bottom right of the chat window.
When games are created you will be able to see them in your Local Area Network tab in Warcraft III.
If no games are open, just start one and post back in the chat window to let people know to look.
That should get you into a game!