After you've downloaded and installed the Nexon Launcher, you'll get the log in screen below:
Once you enter your information, you'll be taken to a home screen which shows each game on the Launcher. Once you select a game, it will take you to the following page, which will include most information one would need pertaining to the game.
Here is where you'll be able to redeem your Invitation/Beta Code to download and install the game. After everything has been installed, the only thing left....enjoy being an elite operative and win some games!