Ember and Spring Application

I wanted to create a complete web application end-to-end. I have chosen ember for front-end and spring for back-end and also PostgreSQL for DB. Now I have coded a simple display page on ember side as well as spring side. I have used Ajax calls on ember side and request mapping on spring side.

QUESTION : Now my question is how will ember know to communicate with this server side I have written. How should I run this. I know to run both separately not together.Can anyone help me explaining how this happens Please. Thanks in advance !!