Excellent, thank you for providing the screenshot. This image clearly shows the problem, and it's a very common one when setting up a new Node.js project.
### **Analysis of the Error**
Based on the terminal output you've provided, here is a step-by-step breakdown of what happened:
1. **`cd mvu1-sim/`**: You correctly navigated into the project directory.
2. **`npm start`**: You correctly tried to run the start script.
3. **`npm WARN Local package.json exists, but node_modules missing, did you mean to install?`**: This is the most important clue. `npm` is telling you that while it sees the "recipe" (`package.json`), it doesn't see the "ingredients" (the actual libraries downloaded into a `node_modules` folder).
4. **`sh: 1: parcel: not found`**: This is the fatal error. The `start` script in `package.json` is defined as `parcel index.html`. When `npm` tried to run this command, the operating system could not find the `parcel` program. This is because `parcel` is a dependency that should have been installed into the `node_modules` folder.
**In short, the problem is that the project's dependencies were not installed before you tried to run the application.**
### **Solution: The Correct Steps**
You simply missed one crucial command. Here is the correct sequence to get the simulation running:
1. **Navigate to the directory** (You've already done this):
```bash
cd mvu1-sim
```
2. **Install the dependencies** (This is the missing step):
```bash
npm install
```
This command reads your `package.json` file, downloads all the necessary libraries (`parcel`, `typescript`, `graphology`, `sigma`, `chart.js`, etc.) from the internet, and saves them into a new folder called `node_modules` inside your project.
3. **Run the application** (This will work now):
```bash
npm start
```
After running `npm install`, the `parcel` command will be available to your script, and the development server will start correctly. You can then navigate to `http://localhost:1234` in your browser to see and use the simulation.