SteveRobertsCA is referring to the screen pop when you launch Workstation:
In the above example, change "nesjo02" to the server name where your Registry is running. If the autoconnect property is set, you may not see this screen. If you do not see the screen pop, follow Steve's instructions to "Change Registry" after the Workstation launches.
If you need to connect to multiple Registries, it is best to 'uncheck' the Automatically connect to this registry on startup box. This will allow you to choose from the dropdown list once you've successfully connected.