Added getting started to the README

README.md

@@ -15,7 +15,18 @@ Implemented using:
 - Role-based authorization (only admins can access Users API)
 - No REST API at all
 - Client can get the token from the GraphQL API itself
-- Custom error handling to create descriptive error messages  
+- Custom error handling to create descriptive error messages
+
+### How to use
+All the GraphQL API is exposed in `/graphql`. Except for the `getToken` request, all the queries and mutations require a valid token. For all the User-related requests, that token must belong to an ADMIN users.
+
+1. Get an access token (initial user is created with `admin` and `admin` as credentials) by performing a POST request to `/graphql` endpoint with the following GraphQL body:
+```graphql
+mutation {
+    getToken(username: "admin", password: "admin")
+}
+```   
+2. Run every request with header: `Authorization: Bearer TOKEN`. You can refer to ![the schema](https://github.com/theam/spring-boot-graphql-demo/blob/master/src/main/resources/graphql/mainschema.graphqls) to check the available queries and mutations.
 
 ## License
 MIT License