diff --git a/__wasm/wit-bindgen-sample/README.md b/__wasm/wit-bindgen-sample/README.md
index f26674d..3e59ec0 100644
--- a/__wasm/wit-bindgen-sample/README.md
+++ b/__wasm/wit-bindgen-sample/README.md
@@ -9,4 +9,31 @@ git clone https://github.com/bytecodealliance/wit-bindgen.git
 ```
 
 
+How works:
+
+```text
++---------------------------------------------------------------------+
+|                                                                     |
+| +---------------------------+  +---------------------------+        |
+| | +-----------------------+ |  | +-----------------------+ |        |
+| | |  +-----------------+  | |  | |  +-----------------+  | |        |
+| | |  | User JavaScript |  | |  | |  | User JavaScript |  | |        |
+| | |  +-----------------+  | |  | |  +-----------------+  | | ...... |
+| | |                       | |  | |                       | |        |
+| | | BOA JavaScript Engine | |  | | BOA JavaScript Engine | |        |
+| | |                       | |  | |                       | |        |
+| | +-----------------------+ |  | +-----------------------+ |        |
+| |                           |  |                           |        |
+| | WebAssembly (WASM) Engine |  | WebAssembly (WASM) Engine |        |
+| |                           |  |                           |        |
+| +---------------------------+  +--+------------------------+        |
+|                                   |                                 |
+| WASM Container                    v                                 |
+|                                   fetch(url, [options])             |
+|                                   console.log(message)              |
+|                                                                     |
+|                                                                     |
++---------------------------------------------------------------------+
+```
+