Improved README.md.

README.md

@@ -1,19 +1,63 @@
 # Phantasmal World
 
-Phantasmal World is a suite of tools for Phantasy Star Online.
+[Phantasmal World](https://www.phantasmal.world/) is a suite of tools for Phantasy Star Online.
 
-## For Developers
+## Developers
 
 See [features](./FEATURES.md) for a list of features, planned features and bugs.
 
 ### Getting Started
 
-1. Install Node.js ([https://nodejs.org/](https://nodejs.org/))
+1. Install Node.js ([https://nodejs.org/]())
-2. Install Yarn ([https://yarnpkg.com/](https://yarnpkg.com/))
+2. Install Yarn ([https://yarnpkg.com/]())
 3. `cd` to the project directory
 4. Install dependencies with `yarn`
-5. Launch server on [http://localhost:1623/](http://localhost:1623/) with `yarn start`
+5. Launch server on [http://localhost:1623/]() with `yarn start`
-6. [src/index.ts](src/index.ts) is the application's entry point
+6. [src/index.ts]() is the application's entry point
+
+### Exploring the Code Base
+
+The code base is divided up into a [core](src/core) module, an [application](src/application) module
+and a module per tool (e.g. [quest_editor](src/quest_editor)). The core module contains the base
+code that the other modules depend on. The application module contains the [main application view](
+src/application/gui/ApplicationView.ts) that provides navigation between the different tools. The
+application view lazily loads and initializes the necessary modules. Each other module represents
+a tool such as the quest editor or the hunt optimizer.
+
+#### Submodules
+
+All modules have an index.ts file that contains an initialization function. They then have several
+common submodules such as controllers, gui, model and stores and some module-specific submodules.
+
+##### GUI
+
+The gui submodule contains views which contain minimal logic. They simply display what their
+controller provides and forward user input to it. Their only dependency is the DOM and a single
+controller.
+
+##### Controllers
+
+The controllers submodule contains the [controllers](src/core/controllers/Controller.ts) on which
+views depend. Usually the view-controller relationship is one-to-one, sometimes it's many-to-one
+(e.g. when a view has many subviews that work with the same data). A controller usually extracts
+data from a shared store and transforms it into a format which the view can easily consume.
+
+##### Model
+
+The model submodule contains observable model objects. Models expose read-only observable properties
+and allow their properties to be changed via setters which validate their inputs.
+
+##### Stores
+
+The stores submodule contains shared data [stores](src/core/stores/Store.ts). Stores ensure that
+data is loaded when necessary and that the data is deduplicated. Stores also contain ephemeral
+shared state such as the currently selected entity in the quest editor.
+
+#### Some Interesting Parts of the Code Base
+
+Phantasmal contains parsers for many of the client's formats in [src/core/data_formats](). The
+[src/quest_editor/scripting]() directory contains an assembler, disassembler, (partly implemented)
+virtual machine and data flow analysis for the PSO scripting byte code.
 
 ### Unit Tests