diff --git a/README.md b/README.md
index af59e42..701e720 100644
--- a/README.md
+++ b/README.md
@@ -4,7 +4,7 @@
 [![Travis build status](http://img.shields.io/travis/gajus/create-index/master.svg?style=flat-square)](https://travis-ci.org/gajus/create-index)
 [![js-canonical-style](https://img.shields.io/badge/code%20style-canonical-blue.svg?style=flat-square)](https://github.com/gajus/canonical)
 
-`create-index` program creates ES6 `./index.js` file in target directories that imports and exports all sibling files and directories.
+`create-index` program creates (and maintains) ES6 `./index.js` file in target directories that imports and exports sibling files and directories.
 
 ## Implementation
 
@@ -18,7 +18,7 @@ If there is no `./index.js`, it will create a new file, e.g.
 
 Created index file must start with `'create index';\n\n`. This is used to make sure that `create-index` does not accidentally overwrite your local files.
 
-If there are sibling files, index file will import them and export, e.g.
+If there are sibling files, index file will `import` them and `export`, e.g.
 
 ```sh
 children-directories-and-files git:(master) ✗ ls -lah
@@ -30,7 +30,7 @@ drwxr-xr-x   2 gajus  staff    68B  6 Jan 15:29 foo
 -rw-r--r--   1 gajus  staff     0B  6 Jan 15:29 foo.js
 ```
 
-Given the above directory contents, index will be:
+Given the above directory contents, `./index.js` will be:
 
 ```js
 'create index';
@@ -44,13 +44,19 @@ export {
 };
 ```
 
-If there are files with the same name as directories in the same directory, file will take precedence.
+When file has the same name as a sibling directory, file `import` takes precedence.
 
 Directories that do not have `./index.js` in themselves will be excluded.
 
+When run again, `create-index` will update existing `./index.js` if it starts with `'create index';\n\n`.
+
+If `create-index` is executed against a directory that contains `./index.js`, which does not start with `'create index';\n\n`, an error will be thrown.
+
 ## Using CLI Program
 
 ```sh
+npm install create-index
+
 create-index ./directory1 ./directory2 ./directory3 ...
 ```