Setting fields and getting Ember Observers to function correctly

I'm brand new to Ember, and have for the past few days been working on getting some simple HTML & JavaScript code to run with the Ember framework. I have built a page that is supposed to print out the longitude/latitude for an entered address, as well as fill a text-field with a specific email address; based on a selection from a drop-down menu. The code I have is as follows:

My JavaScript code; app/routes/demo.js

import Ember from 'ember';
var google = window.google; // jshint ignore:line

export default Ember.Route.extend({

  model() {
    var prepopulatedCounties = Ember.A();
    prepopulatedCounties.pushObject(Ember.Object.create({ value: "1", display: "County1" }));
    prepopulatedCounties.pushObject(Ember.Object.create({ value: "1", display: "County2" }));
    prepopulatedCounties.pushObject(Ember.Object.create({ value: "1", display: "County3" }));
    prepopulatedCounties.pushObject(Ember.Object.create({ value: "1", display: "County4" }));
    prepopulatedCounties.pushObject(Ember.Object.create({ value: "1", display: "County5" }));
    prepopulatedCounties.pushObject(Ember.Object.create({ value: "1", display: "County6" }));
    prepopulatedCounties.pushObject(Ember.Object.create({ value: "1", display: "County7" }));
    prepopulatedCounties.pushObject(Ember.Object.create({ value: "1", display: "County8" }));
    prepopulatedCounties.pushObject(Ember.Object.create({ value: "1", display: "County9" }));
    prepopulatedCounties.pushObject(Ember.Object.create({ value: "3", display: "County10" }));
    prepopulatedCounties.pushObject(Ember.Object.create({ value: "2", display: "County11" }));
    prepopulatedCounties.pushObject(Ember.Object.create({ value: "3", display: "County12" }));

    return Ember.Object.create({
      counties       : prepopulatedCounties,
      selectedCounty : undefined,
      address        : undefined,
      email          : undefined,
      latitude       : undefined,
      longitude      : undefined,
    });
  },

  actions: {
    codeAddress() {
      var geocoder = new google.maps.Geocoder();
      var address  = this.get('currentModel.address');
      alert("Address entered:" + address);

      geocoder.geocode( {'address': address}, function(results, status) {
        if (status === google.maps.GeocoderStatus.OK)
        { 
          var latitude  = results[0].geometry.location.lat();
          var longitude = results[0].geometry.location.lng();

          alert("Latitude: " + latitude + "Longitude: " + longitude);
          this.set('currentModel.latitude', latitude);
          this.set('currentModel.longitude', longitude);
        }
        else
        {
          alert("Geocode was not successful for the following reason: " + status);
        }
      }); 
    },

    setEmail() {
      var dataValue = this.get('currentModel.selectedCounty');

      if(dataValue==="1"){
          this.set('currentModel.email', "first@email.com");
      }
      else if(dataValue==="2"){
          this.set('currentModel.email', "second@email.com");
      }
      else if (dataValue==="3"){
          this.set('currentModel.email', "third@email.com");
      }
      else{
          this.set('currentModel.email', "None Selected");
      }
    }
  }
});

My HTML; app/templates/demo.hsb

<form name="myform">
    <div>
        Address:
        <br>
        
        <button class="button" >Code Address</button>
    </div>
    <div>
        <br>
        Latitude&emsp;&emsp;&emsp;&emsp;&emsp;Longitude:
        <br>
        
        
    </div>
    <br>
    <div>
        <br>
        Email:
        <br>
        
    </div>
    <div>
        <br>
        Counties:
        <br>

        
          Choose One
          
            
          
        
    </div>
</form>

My first question: When I run ember serve I'm able to see the page nicely, but when I enter an address, the text-fields for longitude/latitude does not get filled with anything (I do see the coordinates in the alert); how do I fill these fields properly?

Second question: I've been looking into Ember Observers, but do not fully understand how they work - in my case, how can I use an observer to set the email address to the email text-field when the selected county changes?

Thank you for helping!