How to start a React Native project?

Question

JavaScript

In the command line I write npm start
Starting packager appears ... And the process hangs for an unclear reason.
Package.json content:
"scripts": {
"start": "react-native-scripts start"
...
}
There is a babelrc file:
{
"presets": ["babel-preset-expo"],
"env": {
"development": {
"plugins": ["transform-react-jsx-source"]
}
}
}

Answer 1

is port 8081 free on the system?

Answer 2

Close all node processes.
react-native start