AppDelegate show many Error

In sheet 4. Create Firebase console Project.

when i Configure Firebase in AppDelegate. so many error.
for example
line 24 -> mistake message (Cannot find type 'GIDSignInDelegate' in scope)
line 51 -> Cannot find 'FirebaseApp' in scope
line 52-> Value of type 'GIDSignIn' has no member 'delegate'

Start with sheet 4, “Create Firebase console Project,” and inspect the Firebase setup in AppDelegate around lines 24, 51, and 52. Compare the documented setup with the project’s current dependencies and configuration; done means the listed compile errors no longer occur when configuring Firebase.

Written by the indexing model from the issue text.