For obtaining Firebase JSON file for firestore connection :
Step 1 : Go to Firebase.com
Step 2 : If you have a Firebase account, Sign in, else create an accountStep 3 : Click on Get Started Step 4 : Click on Create a ProjectStep 5 : Enter Project name and tick mark the checkbox to accept Firebase terms.Step 6 : Click on ContinueStep 7 : Select "Set up Google Analytics for my project" and click on ContinueStep 8 : Open Configure Google Analytics dropdown menu and tick mark the checkbox to accept both the terms and conditions.Step 9 : Click on Create ProjectStep 10 : Click on Continue
Step 11: Click on Cloud Firestore under Build
Step 12: Click on Create Database.
Step 13: After clicking on Create Database, a popup will open where you can create a database with specific rules. Select Start in Production Mode and click on Next.
Step 14: Select your Cloud Firestore location and click on Enable.
Note: Once you have set the location, you cannot change it later.
Step 15: Once done, your Firestore database will be created. Now, click on the gear icon in the top left.
Step 16: Click on Project Settings.
Step 17: Under Project Settings, click on the Service Accounts tab.
Step 18: Click on Generate New Private Key to generate a private key file for your service account.
Step 19: After clicking on Generate New Private Key, a pop-up will open for confirmation. Click on Generate Key and securely store the JSON file containing the key.
Step 20: Upload the downloaded file on the creator software.