gameNetwork.show(“leaderboards”) will show a dialog created by Google Play that lists all of your app’s leaderboards. The player can then select which leaderboard they want to view to get details on that leaderboard.
If you want to show just a specific leaderboard, you would have to build your own using gameNetwork.request() and the appropriate function to retrieve a list of scores for a given leaderboard and display them however you want.