If you get the error "node command not found", it means that the Node.js command line interface is not installed on your system or it is not added to your system's path. To fix this error, you need first to make sure that you have installed Node.js on your system. You can download the latest version of Node.js from the official website (https://nodejs.org/en/).
Once you have installed Node.js, you need to add it to your system's path to run the node command from anywhere on your system. The exact steps for adding Node.js to your system's path will vary depending on your operating system. Here are some general instructions that should work on most systems:
Open the "System Properties" dialogue on your computer. On Windows, you can do this by pressing the Windows key + R, typing "sysdm.cpl" into the Run dialogue, and then pressing Enter. On macOS, you can open the "System Properties" dialogue by going to the Apple menu and selecting "About This Mac".
In the "System Properties" dialogue, go to the "Advanced" tab and click on the "Environment Variables" button.
In the "Environment Variables" dialogue, look for the "Path" variable under the "System Variables" section and click on the "Edit" button.
In the "Edit environment variable" dialogue, click on the "New" button and add the path to the Node.js installation directory to the list of paths. On most systems, this directory will be something like "C:\Program Files\nodejs" or "/usr/local/bin".
Click on the "OK" button to save your changes and close the dialogue.
After you have added Node.js to your system's path, you should be able to run the node command from anywhere on your system. To test this, open a new command prompt or terminal window and type node -v to verify that the Node.js command line interface is installed and working properly.