Using tour library with ionic scroll box

I have an ionic scrollbox and a help button that on clicking activates a tour instance form the nzTour class. I have been able to change the slidebox to it’s subsequent pages using the after element of object, however it dawned on me that I have no way to navigate to the previous page if someone presses the back button on the tour. I’m not sure how to correct this, nor do I know if there are any tour libraries are able to do this. Any help is appreciated. Example code is below:

    target: "#contactTether",
    content: "Either an email or contact number must be enterd, however both would be nice."
    target: "#autoFillTether",
    content: "Click this button to auto populate the form from your contacts."
    target: "#nextPageTether",
    content: "Click to head to the next page of the form.",
    after: function(){
      var deferred = $q.defer();
      return deferred.promise;