diff --git a/README.md b/README.md
index ec78fd0f..71ad8bdb 100644
--- a/README.md
+++ b/README.md
@@ -1,2 +1,46 @@
-# Participating in tag translation
+# Tag translation
 
+Tags will be updated every day at 00:00 UTC
+
+## Participating in tag translation
+
+### Rules
+* Each translation file should be located in the root folder
+* Each translation file should be named in following format: [`<ISO 639-1 Code>.json`](https://en.wikipedia.org/wiki/List_of_ISO_639-1_codes)
+* Each translation file should be formatted as JSON file
+
+### 1. Access Editor
+
+If the target file does not exist, go to 1-1  
+If the target file exists, go to 1-2
+
+### 1-1. Add language file
+
+If the target language file doesn't exist, you have to create one.
+
+Click `Create New File` Button at the upper right corner  
+![](https://github.com/tom5079/Pupil/blob/tags/docs/images/add-file.PNG?raw=true)
+
+Name the file according to the naming rule  
+![](https://github.com/tom5079/Pupil/blob/tags/docs/images/filename.png?raw=true)
+
+Copy-paste all the content of [`template.json`](https://raw.githubusercontent.com/tom5079/Pupil/tags/template.json)
+
+### 1-2. Edit Existing File
+
+Click the file to edit and click Pen icon located at the upper right corner
+![](https://github.com/tom5079/Pupil/blob/tags/docs/images/edit-file.png?raw=true)
+
+### 2. Make Necessary Changes
+
+Use text editor shown on screen to make changes
+
+### 3. Propose Changes
+
+When you're done with your changes, Scroll down to the bottom of the page and click `Propose Changes`  
+
+You don't have to provide any commit messages  
+
+![](https://github.com/tom5079/Pupil/blob/tags/docs/images/propose-changes.png?raw=true)
+
+The changes will be applied after review