updated the readme with installation instructions

extension/README.md

@@ -1,6 +1,18 @@
 ## AI Writer Extension
 
 Extension allows injecting api responses into the current 
-textfield. Currently works only one [Calmly](https://www.calmlywriter.com/online/)
+text-field. Currently, works only one [Calmly](https://www.calmlywriter.com/online/)
+
+### Installation
+
+- Download the extension from the release.
+- Drag and drop in the extension tab of your browser
+  - Navigate to `chrome://extensions/`
+- Once installed, click the extension add your `API_KEY`
+- Visit [Calmly](https://www.calmlywriter.com/online/)
+  - Write a prompt: (ex. a life in outer-space)
+  - Select the prompt 
+  - Right click and select `AI Writer: Generate Short Story`
+  - Once response is generated, it will replace the content in text-field