This article will help you to understand How to use Workbench environment in Salesforce for getting URL in REST API calls, REST Explorer panel of salesforce workbench, REST API call for fetching any data and Query understanding and pass queries with Salesforce REST API.

Workbench is a collection of tools for interacting with your Salesforce through the API. Workbench provides a friendly environment especially for Salesforce APIs, it’s the perfect way to go deeply go inside and test your API's before you’re finalized your actual code integration.