Better readme

Author: chenglou

README.md

@@ -18,3 +18,30 @@ For now, you have to clone the repo and run `npm run compile`. The language serv
 ### Upcoming Features
 - Formatting of temporary files
 - Type diagnosis
+
+## Develop
+
+### Structure
+
+```
+.
+├── client // Language Client
+│   ├── src
+│   │   └── extension.ts // Language Client entry point
+├── package.json // The extension manifest.
+└── server // Language Server
+    └── src
+        └── server.ts // Language Server entry point
+```
+
+### Running the Project
+
+- Run `npm install` in this folder. This installs all necessary npm modules in both the client and server folder
+- Open VS Code on this folder.
+- Press Ctrl+Shift+B to compile the client and server.
+- Switch to the Debug viewlet (command palette -> View: Show Run and Debug).
+- Select `Launch Client` from the drop down.
+- Run the launch config.
+- If you want to debug the server as well use the launch configuration `Attach to Server`
+- In the [Extension Development Host] instance of VSCode, open a document in 'plain text' language mode.
+- Try `ReScript` mode formatting with `.res` or `.resi` files.