未安装ReactJS

如何解决未安装ReactJS

我一直在尝试使用方法npx和npm在我的PC上安装React。我无法启动我的自定义React应用。
我检查了其他答复，但不满意。

My current node version is 12.16.2

My current npm version is 6.14.8

我的package.json文件是：

"name": "myapp","version": "0.1.0","private": true,"dependencies": {
 "@testing-library/jest-dom": "^4.2.4","@testing-library/react": "^9.5.0","@testing-library/user-event": "^7.2.1","react": "^16.13.1","react-dom": "^16.13.1","react-scripts": "3.4.3"
},"scripts": {
 "start": "react-scripts start","build": "react-scripts build","test": "react-scripts test","eject": "react-scripts eject"
},"eslintConfig": {
 "extends": "react-app"
},"browserslist": {
 "production": [
   ">0.2%","not dead","not op_mini all"
 ],"development": [
   "last 1 chrome version","last 1 firefox version","last 1 safari version"
 ]
}
}

我已经被困了几个小时了。非常感谢您的帮助。