Update README.md

Author: CoderJava

README.md

@@ -1,6 +1,9 @@
 # Flutter News App
 News App developed with Flutter and API from [News API](https://newsapi.org)
 
+## How to use
+Please open file **api_provider.dart** and change `apiKey` in variable `_baseUrl` with your own.
+
 ## Technology
 1. BLoC<br />
 BLoC (Business Logic Component) is design pattern helps to separate *presentation* from *business logic*.
@@ -15,4 +18,4 @@ Flutter plugin for launching a URL on Android and iOS.
 6. Build Runner<br />
 Package to provides a concrete way of generating files using Dart code, outside of tools like `pub server/build`, files are always generated directly on disk, and rebuilds are *incremental-* inspired by tools such as Bazel.
 
-![News App](https://github.com/CoderJava/Flutter-News-App/blob/master/screenshots/output_app.png)
+![News App](https://github.com/CoderJava/Flutter-News-App/blob/master/screenshots/output_app.png)