Created App with Firebase Studio,Can't find API key

I’ve created an app using Firebase Studio and found an error below.
‘’’
Firebase environment variables are not set. Please configure .env and make sure to set NEXT_PUBLIC_FIREBASE_API_KEY, NEXT_PUBLIC_FIREBASE_AUTH_DOMAIN, NEXT_PUBLIC_FIREBASE_PROJECT_ID, NEXT_PUBLIC_FIREBASE_STORAGE_BUCKET, NEXT_PUBLIC_FIREBASE_MESSAGING_SENDER_ID, and NEXT_PUBLIC_FIREBASE_APP_ID
‘’’

And i found that .env file is empty.
I visited firebase console and checked project page, but the app doesn’t appear.
so i can’t create new api key…
What should i do? I’m confused…