Normal dev veda kranna nan => npm run dev
Build krala nan =>

npm run build npm start

Apita ghnna one command eka mkkda kiyla package.json eke scripts section eken hoya ganna pluvn

"scripts": {
"dev": "next dev",
"build": "next build",
"start": "next start",
"lint": "next lint"
}

both are same bro the only difference is react and nextjs developed by big companies.