After entering a license key that includes Failover features and that designates the machine on which WhatsUp Gold is being installed will serve as the Secondary site, you'll simply continue with the workflow described in Install WhatsUp Gold using either the Standard or Advanced workflow. There are no additional installation dialogs specific to the Secondary Site configuration.

After entering a license key that includes Failover features and that designates the machine on which WhatsUp Gold is being installed will serve as the Primary site, you'll be prompted to complete the following steps at the appropriate points during installation in addition to everything described in Install WhatsUp Gold using either the Standard or Advanced workflow.

Review the information presented in the Deployment Options dialog, then click Next.

Enter SQL Server name (using the IP address of the Secondary site, database instance name if you are not using the default, and port number if necessary) and sysadmin credentials so the setup program has permissions to create a new SQL Server login for WhatsUp Gold. Please note, the sysadmin login is only used during WhatsUp Gold installation and is not stored anywhere. Click Next.

Please note, this dialog also gives you the option to Use Windows Authentication. If this option is enabled, the Login Name and Password are not required. However, the user logged in at the time of installation must be a system administrator on the specified SQL Server to proceed without generating an error.
Important: When installing WhatsUp Gold in a Failover configuration, you MUST install the Secondary site prior to installing the Primary site.
Important: To successfully complete installation of WhatsUp Gold using Failover features, proceed with Finalize Failover configuration following installation.