Missing concept? Return to where I came from

I am a windows/mac developer. VB3-6/Winforms/WPF/Java (on both Win/Mac). Often an application needs to know what form to display next, like when a form replaces the whole application (SDI app) and that form can be accessed from several different forms. I cannot find how to do that in Ember. Since Ember apps are SDI by default (only one presentation “window” for the whole application) and I might need to access a “Add item” form from multiple other forms. How does Ember know where you came from?

Obviously so you can go back there when you’re done. I wanted to do this with query string parameters but can’t find a version of Ember that will load a version of handlebars that supports query strings with the link-to helper.