Ideally, you would have mapped your old site first and made a list of ALL the urls there are. Then you would make 301 redirects from ALL of those old urls to new urls in your new site, making sure that every old link url points to a new one.
It doesn't matter . . . by implementing a 301 redirect for each old url to a new one, you are telling Google (and others) that "this" page has moved to "this" page.