I have tried to write a web app but I have a problem connecting it to the database. can someone help me? this is my code.

import firebase from 'firebase/compat/app';
import 'firebase/compat/auth';
import 'firebase/compat/firestore';



import Movie from '../components/Movie.vue'
import Seat from '../components/Seat.vue'


const config = {
  apiKey: "AIzaSyBbSgMfe474LIuWTuMvqoF6A8n7PtRF-ac",
  authDomain: "vuetest-76268.firebaseapp.com",
  databaseURL: "https://vuetest-76268-default-rtdb.firebaseio.com",
  projectId: "vuetest-76268",
  storageBucket: "vuetest-76268.appspot.com",
  messagingSenderId: "886558080944",
  appId: "1:886558080944:web:775edb745e8c99dee16075"
};

firebase.initializeApp(config)

var db = firebase.database()
var dbRef = db.ref('/')
dbRef.set('xxx')

i think i do something wrong. how can i set 'xxx' in my firebase database