npm ERR! Missing script: "start" npm ERR! npm ERR! code example

Example 1: npm ERR! missing script: start

"scripts": {
   "start": "node app.js"
},

Example 2: npm ERR! missing script: start

Error: C:\Users\noname\Desktop\Conestoga\Level-2\Sem-3\Data Connectivity\Assingment\New 1\Assingment1\app_server\views\index.pug:24:1
    22|                      span.carousel-control-next-icon(aria-hidden="true")
    23|                      span.sr-only Previous
  > 24|                     a.carousel-control-next(href="#carouselExampleIndicatores" role="button" data-slide="next")
--------^
    25|                         span.carousel-control-next-icon(aria-hidden="true")
    26|                         span.sr-only Next 
    27|     //- h1= name 

Inconsistent indentation. Expecting either 16 or 21 spaces/tabs.
    at makeError (C:\Users\noname\Desktop\Conestoga\Level-2\Sem-3\Data Connectivity\Assingment\New 1\Assingment1\node_modules\pug-error\index.js:32:13)
    at Lexer.error (C:\Users\noname\Desktop\Conestoga\Level-2\Sem-3\Data Connectivity\Assingment\New 1\Assingment1\node_modules\pug-lexer\index.js:58:15)
    at Lexer.indent (C:\Users\noname\Desktop\Conestoga\Level-2\Sem-3\Data Connectivity\Assingment\New 1\Assingment1\node_modules\pug-lexer\index.js:1212:18)
    at Lexer.callLexerFunction (C:\Users\noname\Desktop\Conestoga\Level-2\Sem-3\Data Connectivity\Assingment\New 1\Assingment1\node_modules\pug-lexer\index.js:1319:23)
    at Lexer.advance (C:\Users\noname\Desktop\Conestoga\Level-2\Sem-3\Data Connectivity\Assingment\New 1\Assingment1\node_modules\pug-lexer\index.js:1358:15)
    at Lexer.callLexerFunction (C:\Users\noname\Desktop\Conestoga\Level-2\Sem-3\Data Connectivity\Assingment\New 1\Assingment1\node_modules\pug-lexer\index.js:1319:23)
    at Lexer.getTokens (C:\Users\noname\Desktop\Conestoga\Level-2\Sem-3\Data Connectivity\Assingment\New 1\Assingment1\node_modules\pug-lexer\index.js:1375:12)
    at lex (C:\Users\noname\Desktop\Conestoga\Level-2\Sem-3\Data Connectivity\Assingment\New 1\Assingment1\node_modules\pug-lexer\index.js:12:42)
    at Object.lex (C:\Users\noname\Desktop\Conestoga\Level-2\Sem-3\Data Connectivity\Assingment\New 1\Assingment1\node_modules\pug\lib\index.js:99:27)
    at Function.loadString [as string] (C:\Users\noname\Desktop\Conestoga\Level-2\Sem-3\Data Connectivity\Assingment\New 1\Assingment1\node_modules\pug-load\index.js:44:24)