Google Custom Search using terms:
App to App Link SAPUI5
Or
Navigation Link SAPUI5
Lots of stuff to wade through, but I think you will find what you are looking for with this search (much better than the SCN Search functionality). I would also suggest that you visit the SAPUI5 Developer Center which is where most of the SAPUI5 content related to Fiori apps is located.
Regards, Mike (Moderator)
SAP Technology RIG