In this guide, I’m going to create a Lightning component with a list display of contact details. The data feeding the list comes from an external service via a REST API.
Creating the Lightning component

Most operations take place in the Developer Console. To open it, click on the gear in the top right-hand corner. To access the full range of development possibilities (webservice access), it is essential to carry out development and testing in a sandbox organization. Salesforce does not authorize development directly on the production organization.

As a small aside, in order to move your code from the sandbox to production, you must have sufficient code coverage for the APEX classes to be developed.

In the Developer Console, select File->New-> Lightning Component :

Enter the desired information for the component name and the desired options for integrating the component into lightning elements. Once creation has started, the Developer Console will change the display to show the list of required and optional elements.