1) Get Warcraft 3 RoC and TFT and install them.
2) Once you have that installed check if it's working.
3) Update your TFT patch to the current version (1.22a) with this guide, Read for the problem before ask..^_^
4) Make a folder in your C:/Program Files/Warcraft 3/Maps/Download
5) go to http://www.getdota.com and download the latest DotA map or you can download old map in this link
6) Save it to your download folder in C:/Program Files/Warcraft 3/Maps/Download
7) Run your TFT and click single player > custom game > go to your download folder and click on your DotA map and press start game.
8) Now you should have DotA installed in your warcraft you can go play
in Battle.net and you should have warcraft 3 loader for battle.net. you
ca visit this link
9) If you want playing dota online read this guide
10) If You want information about DotA read DotA FAQ
