Converting website pages to SiteBuilder Plus

I just purchased a new Mac and found out the SiteBuilder Download is not compatible with a Mac and that I need to use SiteBuilder Plus.  That is fine, but since I manage several sites with hundreds of pages, how can I convert everything I've created on the desktop version to SiteBuilder Plus?  I assume there must be a solution for this.  I noticed that many of the pages I published on the desktop version appear as a page on Sitebuilder Plus while many others that have been published do not.  Please advise.  Thank you