Click on Downloads > Game Client to download the game. If you had previously installed the game, click on manual patches to download the latest updates. Alternatively, you may just start the game as per normal and let it update automatically.
Double click on the installation program after downloading the game client and follow the step by step instructions to install the game. If you wish to change the folder settings, please click on the 'Browse' button to install in a different folder.
Note: It is highly recommended that you use the default settings to install the game.
Once the installation is complete, click on the 'Counter-Strike Online' Shortcut icon on your desktop to start the game.
Before you start, you will need an IAHGames Passport account to proceed. Sign up for a FREE account here if you do not have one.