you have to go to the 'objectdock properties' menu, either by clicking on the 'configure dock' icon if you have one or right clicking in an empty area on the dock and clicking on 'dock settings.' then in the 'general' tab, click at the bottom on the 'manage my docks' button. then click the 'create new dock' button and you're on your way.
btw this is for the registered version of objectdock plus
i have a two monitor setup and have a dock on the top of my left screen and a small taskbar dock at the bottom of my right screen so i don't have to send my mouse all the way to the bottom corner of the left screen to switch apps.