There might arise a recurring compaatibility issue with node and npm versions. You might have npm 6.x version installed and node 21.x v installed. So, just make one of it upgraded to compatible version. Here, I just downgrade node version to 10.x(compatible to npm 6.x) using: nvm use 10.

Check node and npm version using: node -v and npm -v , if the versions are compatible before running.

To intsall all the required dependecies

npm install

Start the project

npm start

Runs the app in the development mode.
Open http://localhost:3000 to view it in the browser.

Test the application

npm test

Launches the test runner in the interactive watch mode.
See the section about running tests for more information.

Build application

npm run build

Builds the app for production to the build folder.