In order to login, you will be asked for your username and password. You can find your username in the activation email that you received upon your registration. If you do not remember your password, please check how to recover it via the "Forgot your password?" functionality on the login screen.
To download the software you will have to sign in to your Chaos account then go to the Downloads section. Once you have accessed the Downloads section, select your product and then use the filters and search to find the build you would like to download.