How to use the single-spa.start function in single-spa

// // app2: The URL "/app2/..." is being redirected to "http://localhost:9002/..." this is done by the webpack proxy (webpack.config.js)
  // loadingPromises.push(loadApp('app2', '/app2', '/app2/singleSpaEntry.js', '/app2/store.js', globalEventDistributor));

  // // app3: The URL "/app3/..." is being redirected to "http://localhost:9003/..." this is done by the webpack proxy (webpack.config.js)
  // loadingPromises.push(loadApp('app3', '/app3', '/app3/singleSpaEntry.js', null, null)); // does not have a store, so we pass null

  // // app3: The URL "/app4/..." is being redirected to "http://localhost:9004/..." this is done by the webpack proxy (webpack.config.js)
  // loadingPromises.push(loadApp('app4', '/app4', '/app4/singleSpaEntry.js', null, null)); // does not have a store, so we pass null

  // // app5: The URL "/app5/..." is being redirected to "http://localhost:9005/..." this is done by the webpack proxy (webpack.config.js)
  // loadingPromises.push(loadApp('app5', '/app5', '/app5/singleSpaEntry.js', '/app5/store.js', globalEventDistributor));

  // wait until all stores are loaded and all apps are registered with singleSpa
  await Promise.all(loadingPromises);

  singleSpa.start();
}

// app1: The URL "/app1/..." is being redirected to "http://localhost:9001/..." this is done by the webpack proxy (webpack.config.js)
    await loadApp('app1', '/app1', '/app1/singleSpaEntry.js', '/app1/store.js', globalEventDistributor);

    // app2: The URL "/app2/..." is being redirected to "http://localhost:9002/..." this is done by the webpack proxy (webpack.config.js)
    await loadApp('app2', '/app2', '/app2/singleSpaEntry.js', '/app2/store.js', globalEventDistributor);

    // app3: The URL "/app3/..." is being redirected to "http://localhost:9003/..." this is done by the webpack proxy (webpack.config.js)
    await loadApp('app3', '/app3', '/app3/singleSpaEntry.js', null, null); // does not have a store, so we pass null

    // app3: The URL "/app4/..." is being redirected to "http://localhost:9004/..." this is done by the webpack proxy (webpack.config.js)
    await loadApp('app4', '/app4', '/app4/singleSpaEntry.js', null, null); // does not have a store, so we pass null

    // app5: The URL "/app5/..." is being redirected to "http://localhost:9005/..." this is done by the webpack proxy (webpack.config.js)
    await loadApp('app5', '/app5', '/app5/singleSpaEntry.js', '/app5/store.js', globalEventDistributor);

    singleSpa.start();
}

if (!auth.getAuthTokenAsBearer()) {
        singleSpa.navigateToUrl('#' + routing.signInRoute)
      }
    }
  })

  window.addEventListener('single-spa:before-routing-event', () => {})

  window.addEventListener('single-spa:routing-event', () => {
    telemetry.mixpanel.register({
      $current_url: routing.getPathInLocationHash(),
    })
    telemetry.mixpanel.track('PageChange')
  })

  singleSpa.start()
}

singleSpa.navigateToUrl('#' + registry.getDefaultRouter())
  }

  window.addEventListener('single-spa:app-change', () => {
    if (!routing.isSignInPage()) {
      if (!auth.getAuthTokenAsBearer()) {
        singleSpa.navigateToUrl('#' + routing.signInRoute)
      }
    }
  })

  window.addEventListener('single-spa:first-mount', () => {
    removeSpinner()
  })

  singleSpa.start()
}

async function bootstrap() {
    let projectConfig = await SystemJS.import('/project.config.js' )
    projectConfig.projects.forEach( element => {
        registerApp({
            name: element.name,
            main: element.main,
            url: element.prefix,
            store:element.store,
            base: element.base,
            path: element.path
        });
    });

    singleSpa.start();
}

prefetchAll(microApps, fetch);
      break;

    default:
      break;
  }

  if (jsSandbox) {
    useJsSandbox = jsSandbox;
  }

  if (singular) {
    singularMode = singular;
  }

  startSpa();

  frameworkStartedDefer.resolve();
}

function startApp() {
  registerApplication(
    'app1',

    async () => await window.SystemJS.import('/app1/app1.js'),

    (location) => location.pathname.startsWith('/ex1'),

    { sampleProp: 'just some random string' },
  );

  start();
}
startApp();