diff --git a/README.md b/README.md
index f0c1ca4..2e44c52 100644
--- a/README.md
+++ b/README.md
@@ -1,7 +1,22 @@
-# <sub><img src="src/icons/48.png"></sub> Simple Translate
+# <sub><img src="/src/icons/64.png" width=64px height=64px></sub> Simple Translate  
 
-#### View translations easily as you browse the web. [<img align="right" src="https://addons.cdn.mozilla.net/static/img/addons-buttons/AMO-button_2.png">](https://addons.mozilla.org/firefox/addon/simple-translate/)
+#### Quickly translate selected text on web page. In toolbar popup, you can translate input text.  
 
----
+[<img src="https://addons.cdn.mozilla.net/static/img/addons-buttons/AMO-button_1.png" align="left" alt="for Firefox">](https://addons.mozilla.org/firefox/addon/simple-translate/)  
 
-#### You can contribute by translating Simple Translate on [Crowdin](https://crowdin.com/project/simple-translate).
+<br/>
+
+## Translation
+You can contribute by translating Tab Session Manager on **[Crowdin](https://crowdin.com/project/simple-translate)**.  
+
+## Developing
+1. Clone the repository `git clone https://github.com/sienori/simple-translate`
+2. Run `npm install`
+3. Run `npm run watch-dev`
+### Load the extension in Chrome
+1. Open Chrome browser and navigate to `chrome://extensions`
+2. Select "Developer Mode" and then click "Load unpacked extension..."
+3. From the file browser, choose to `tab-session-manager/dev/chrome`
+### Load the extension in Firefox
+1. Open Firefox browser and navigate to `about:debugging`
+2. Click "Load Temporary Add-on" and from the file browser, choose `tab-session-manager/dev/firefox`