chore: readme polished

README.md

@@ -42,7 +42,8 @@ Scan Mode                                      ▼
 
 - Setup env with Nebula-Up following [this guide](https://github.com/wey-gu/nebulagraph-di/blob/main/docs/Environment_Setup.md).
 - Install ngdi with pip from the Jupyter Notebook with http://localhost:8888 (password: `nebula`).
-- Open the demo notebook and run cells with `Shift+Enter` or `Ctrl+Enter`.
+- Open the demo notebook and run cells one by one.
+- Check the [API Reference](https://github.com/wey-gu/nebulagraph-di/docs/API.md)
 
 ## Installation
 
@@ -64,6 +65,7 @@ pip install ngdi
 
 ## Documentation
 
+[Environment Setup](https://github.com/wey-gu/nebulagraph-di/blob/main/docs/Environment_Setup.md)
 [API Reference](https://github.com/wey-gu/nebulagraph-di/docs/API.md)
 
 ## Usage