> ## Documentation Index > Fetch the complete documentation index at: https://docs.coreflux.org/llms.txt > Use this file to discover all available pages before exploring further. # Using LoT Notebooks > Use LoT Notebooks as living documentation—run LoT code, document your project, and see MQTT data all in one place. VS Code with a LoT notebook open showing markdown and LoT code cells, Coreflux Explorer and project tree on the left, Data Viewer below, and MQTT connection in the status bar ## Overview **LoT Notebooks** are **living documentation**: Markdown for documentation and runnable LoT code in the same file. You **run LoT** to deploy to the **Coreflux MQTT broker**, document with **Markdown** and use the **Data Viewer** to **see what is happening on the broker**. **Write it, run it, see the result in the broker.** With LoT Notebooks and LoT VS Code Extension, document the "why," deploy the "what," and see the MQTT traffic and execution logic side by side with your notebook. ## Before you start * **Visual Studio Code** installed * A **Coreflux broker** installed or in another machine you can reach ## Install and connect Animated walkthrough: VS Code Extensions view, search for coreflux, install Coreflux LoT, Coreflux icon appears in the Activity Bar 1. Open VS Code. 2. Open the Extensions view in the sidebar (or use the shortcut `Ctrl+Shift+X` on Windows/Linux, `Cmd+Shift+X` on macOS). 3. Search for **LoT Notebooks** by **Coreflux** and install it. VS Code: connect to MQTT broker via LoT extension; status bar shows MQTT connected 1. Click on the MQTT Connection Status on bottom left corner of your VS Code or click **Connect to Broker** in the **Data Viewer** (Coreflux sidebar). 2. Enter your broker **URL**, **username**, and **password**. Use a full URL such as `mqtt://localhost:1883` or `mqtts://your-host:8883` for TLS. | Setting | Example (local defaults) | | -------- | --------------------------------------------- | | URL | `mqtt://localhost:1883` | | Username | `root` | | Password | `coreflux` (change immediately in production) | When you are connected, the status bar shows a green **MQTT: Connected**. If any issues occur, the status bar will become red. ## Create a LoT notebook and deploy your first LoT code LoT Notebook: Create and deploy to broker from a code cell; success feedback and Coreflux Explorer update 1. In the Activity Bar (left bar), open **Coreflux**. 2. Under **PROJECT**, use **New File**, give your **LoT Notebook** a name, and it will be created within the **workspace folder** you opened in VS Code. 3. Add a code cell from the notebook toolbar (**+ Code**). Optionally, add a Markdown cell (**+ Markdown**) to document your code. 4. Write or paste a LoT code (for example the Action below) and click **Execute Cell** icon on the cell or **Run All** option above. ```lot theme={null} DEFINE ACTION Heartbeat ON EVERY 10 SECONDS DO PUBLISH TOPIC "system/heartbeat" WITH TIMESTAMP "UTC" ``` 5. See the data change in the **Data Viewer**, by subscribing to all topics, just like MQTT Explorer. Additionally, you can click on a data topic to see it in more detail, including a replay of the data changes. ## Next Steps Workflow, cells, broker connection, commands, Git, best practices, and troubleshooting. Data Viewer, replay, execution trace, and debug on LoT Notebooks.