add section on archetcture

Author: mssalemi

README.md

@@ -6,6 +6,28 @@ A high-performance API for building Shopify Functions using WebAssembly (WASM).
 
 The Shopify Function WASM API provides a streamlined interface for developing high-performance Shopify Functions. It uses WebAssembly to offer improved execution speed, reduced memory usage, and enhanced security compared to traditional functions.
 
+## Architecture
+
+The WASM API consists of these main components:
+
+1. **Core (`core/`)**
+   - Low-level WASM bindings and memory management
+   - Handles raw memory operations and string handling
+   - Provides the foundation for the API layer
+   - Manages direct WASM imports/exports
+
+2. **API (`api/`)**
+   - High-level interface for writing Shopify Functions
+   - Provides the `#[shopify_function]` macro
+   - Handles input/output operations with a user-friendly API
+   - Built on top of the core package
+
+3. **Trampoline (`trampoline/`)**
+   - Bridges communication between your WASM module and Shopify's runtime
+   - Handles memory sharing between guest and provider modules
+   - Manages string operations and object property access
+   - Creates the necessary WASM imports/exports
+
 ## Getting Started
 
 ### Prerequisites