📝 Add installation documentation

README.md

@@ -19,7 +19,7 @@
 ```
 
 ```css
-  /* After the transformation of RFS Autopilot but before RFS*/
+  /* After the transformation of RFS*/
 .foo {
   font-size: calc(1.525rem + 3.3vw);
 }
@@ -35,7 +35,29 @@
 
 [RFS](https://github.com/twbs/rfs) is a great unit resizing engine that helps you build responsive CSS layout, but writing `rfs()` everywhere manually is a pain in the ass.
 
-With this plugin, you just need to declare rules you want to apply `rfs()` to, and it will do the heavy lifting for you.
+With this plugin, you just need to declare rules you want to apply `rfs()` to, and it will do the heavy-lifting for you.
+
+## Autopilot for RFS, what about freedom?
+
+There is no shortcut for freedom. As we Hong Kongers fighting for our freedom and our very existence, your support is crucial to us.  Check out [what you can do to fight with us]().
+
+## Installation
+
+Input this command in terminal and download this PostCSS plugin.
+
+```
+
+npm i postcss-rfs-autopilot
+
+```
+
+[RFS](https://github.com/twbs/rfs) is treated as an external dependency for this plugin, thus you would need to download and include it manually in your PostCSS config as usual.
+
+```
+
+npm i rfs
+
+```
 
 ## Usage
 
@@ -45,6 +67,8 @@ or `postcss` in bundle config.
 
 If you already use PostCSS, add the plugin to plugins list:
 
+As this plugin only adds `rfs()` to values of your CSS, you have to require it before `rfs` in order to make it useful. 
+
 ```diff
 module.exports = {
   plugins: [
@@ -58,3 +82,7 @@ If you do not use PostCSS, add it according to [official docs]
 and set this plugin in settings.
 
 [official docs]: https://github.com/postcss/postcss#usage
+
+## API Reference
+
+TODO