The following steps are only required if your environment does not have access to React Native auto-linking.

Add the RNFBMessaging Pod to your projects /ios/Podfile:

target 'app' do
  # ...
  pod 'RNFBMessaging', :path => '../node_modules/@react-native-firebase/messaging'
end

You may need to update your local Pods in order for the RNFBMessaging Pod to be installed in your project:

$ cd ios/
$ pod install --repo-update

Once the Pods have installed locally, rebuild your iOS project:

npx react-native run-ios