Step 1: Download and unzip the client to a folder of your choice.
Step 2: Download the launcher and place it in the 'AionReawakening' folder (created after unzipping the client).
Step 3: Double-click 'AionReawakeningLauncher.exe' in the 'AionReawakening' folder to launch the game.
Note: You may get a "potential virus" warning from your browser when downloading the launcher and/or from Windows when running the launcher. This is due to the launcher being a custom-built application, and you can ignore this warning and download/run it anyway.