Have registered extra sidebars but need to assign to specific pages

Hello. I am using the Corbiz theme and can’t seem to get support. I have added extra sidebars, and they show in the Widgets area. Great. But on each new page, there is a Page Options dropdown to choose which sidebar is assigned per page, and I can’t figure out how to add the new sidebar options to this dropdown or to just add each one to a new page. Any help would be greatly appreciated.Thanks.