How to download and play DotA 2 in 5 steps
Step 1: Install Steam client from here: http://store.steampowered.com/about/ (free).
Step 2: Run Steam. From the “Store” tab, write “DotA” in the search bar. Click on “DotA 2″.
Step 3: From the DotA 2 page, click on “play game” > choose where you want to install the game on your PC > next > wait for the game to download. Close that window if you see a button called “finish”. Click on “Library” > all games. Notice DotA 2 downloading in the left side. The game has around 2 gigabytes so be patient.
Step 4: Once the game was downloaded and installed, click the “play” button in order to start the game.
Step 5: Once the game was launched, click on the “play” tab > click on “find a match” from the left panel > click on “Find Match” from the center of the UI.