The way I link to an article is navto://ArticleName# or navto://ArticleName#0. Both will take you to the first page of the article. navto://ArticleName#1 will take you to the second page of the article.
Digital Publishing Suite Help | Hyperlink and button overlays
ArticleName should the the name of the article in your Folio Builder panel and not the name of your Indesign document. I also follow the directory structure for importing articles to keep the path simple. Folio > ArticleName > file_name_h.indd (and file_name_v.indd if you are using dual orientation).
Digital Publishing Suite Help | Structuring folders for importing articles
