How emberjs function is invoked?

I want to understand how the function in plugin is invoked.

Here's the code snippet from discourse-adplugin

export default Ember.Component.extend({
  ...
  _initGoogleDFP: function() {
    var self = this;
    loadGoogle(this.siteSettings).then(function() {
      ...
    });
  }.on('didInsertElement'),
  ...
});

There's no mention that the _initGoogleDFP function is evidently invoking by somebody but it's somehow invokes from guts of emberjs.

What is the principles of initialising emberjs components? How _initGoogleDFP is invoking by emberjs?