Electron app not loading index.html after building with electron builder, even giving no error

I am a beginner to electron and created a simple app with it. it is running correctly using cmd. However after building it with electron-builder and opening the created app it is showing nothing just white screen with electron frame. I think that maybe this is an error in package.json, but not sure where? I have 3 html files, some images in my folder which i want to package. I have seen some examples but don't know what to include inside "files":[ ] in package.json . however i have tried to include all my files which i want to package but still the problem persists this is my package.json-

  "name": "duplichecker",
  "productName": "Multimedia Manager 1.2",
  "version": "1.2.0",
  "description": "delete duplicate and sort images and videos images at a go!",
  "main": "electron-main.js",
  "keywords": [
    "multimedia manager 1.2.0",
    "multimedia manager 1.2",
    "multimedia manager",
  "author": "hemant kumar",
  "license": "ISC", 
  "scripts": {
    "start": "electron .",
    "buildi": "electron-builder",
    "postinstall": "electron-builder install-app-deps"
  "devDependencies": {
    "electron": "^9.2.1",
    "electron-builder": "^22.8.0",
    "webpack": "^4.44.1"
  "dependencies": {},
  "build": {

    "appId": "duplichecker",
      "win": {
      "target": [
      "icon": "build/icon.ico"
    "nsis": {
      "installerIcon": "build/icon.ico",
      "uninstallerIcon": "build/icon.ico",
      "uninstallDisplayName": "Multimedia Manager",
      "license": "license.txt",
      "oneClick": false,
      "allowToChangeInstallationDirectory": true

maybe i have to change the win.loadFile() in main.js but to what?

function createWindow () {
  // Create the browser window.
  const win = new BrowserWindow({
    width: 600,
    height: 400,
    webPreferences: {
      enableRemoteModule: true,
      nodeIntegration: true,
      webSecurity: false
  //maximizes the window;

  // and load the index.html of the app.