Ember js get object from previous route

I am building my first EmberJS app. Initially from index route, i will display an A. When user click A, it will route to /a. Component A will have a field url, after fill in and click a button, it will route to /b. Component B also has a field email. Fill in and click a button it will route to /summary which displays what i filled in A and B. How could I do it in best practice. I am using ember-cli and this.transitionTo(/b)to go to route /b