How to call navigation from onStart activity in jetpack compose

I would like to navigate from my login screen to home screen in case the user is logged in. Being new to kotlin and jetpack compose, I'm not sure how this can be done since SetContent{}
should only be called from on create method and the Navigation() component can only be called from within a composable. Back in Java+XMl format coding we used to use intents and StartActivity(), but since jetpack compose recommends a single activity and multiple screen programming style, I don't understand this

    class MainActivity : ComponentActivity() {
//private lateinit var auth: FirebaseAuth
lateinit var mGoogleSignInClient: GoogleSignInClient
private lateinit var signInLauncher: ActivityResultLauncher<Intent>
override fun onStart() {
super.onStart()
// Check if user is signed in (non-null) and update UI accordingly.
val account = GoogleSignIn.getLastSignedInAccount(this);
if (account != null) {
//            in XML style , we used to use
//            Intent intent = new Intent(LoginActivity.this, UserHomeActivity.class);
//            startActivity(intent);
account.getEmail()?.let { Log.d("Signed In: ", it) };
} else {
Log.d("Signed In: ", "Not signed in");
}
}
override fun onCreate(savedInstanceState: Bundle?) {
val gso =
GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN).requestEmail().build()
mGoogleSignInClient = GoogleSignIn.getClient(
this,
gso
)
signInLauncher = registerForActivityResult(
ActivityResultContracts.StartActivityForResult(),
ActivityResultCallback<ActivityResult> { result ->
val task: Task<GoogleSignInAccount> =
GoogleSignIn.getSignedInAccountFromIntent(result.getData())
handleSignInResult(task)
})
super.onCreate(savedInstanceState)
setContent{
Navigation(mGoogleSignInClient = mGoogleSignInClient, signInLauncher = signInLauncher)
}
private fun handleSignInResult(completedTask: Task<GoogleSignInAccount>
//                                   ,navController: NavController
) {
try {
val account = completedTask.getResult(ApiException::class.java)
val idToken = account.idToken
//            navController.navigate(Screens.UserHomeScreen.route)
//            val intent = Intent(this@LoginActivity, UserHomeActivity::class.java)
//            startActivity(intent)
} catch (e: ApiException) {
Log.w("Sign In Error", "signInResult:failed code=" + e.statusCode)
Toast.makeText(this, "Sign in failed", Toast.LENGTH_SHORT).show()
}
}

Call your NavHost() function inside the setContent {} block in your main activity. In your NavHost() function your startDestination should be your login screen. And move your login logic to the LoginScreen composable. Something similar to below:

override fun onCreate(savedInstanceState: Bundle?) {
NavigationHost(navController = rememberNavController())
}

and

@Composable
fun NavigationHost(navController: NavHostController) {
NavHost(
navController = navController,
startDestination = Screen.LoginScreen.route
) {
...
}
}