Log in to iOS Dev Portal
Under Identifiers -> App IDs section, select your app's build identifier entry.
If Game Center is not enabled under Application Services, click on Edit and enable it.
When submitting via iTunes Connect make sure you set Game Center switch to on.
For more information, please refer Game Services Setup Guide.
Game Services on Android rely on Google Play Services. You can enable Google Play Services by following below steps.
Open Google Play Developer Console and Click on Game Services Tab.
Click on Add New Game if you are setting up freshly.
Specify If your game already uses Google API's.
If not, click on "I don't use any Google APIs in my game yet".
Fill in the details and click continue.
Now you will be in Game Details page.
Fill in the details and go to "API CONSOLE PROJECT" section.
Turn on the API's required button to make Play Services work.
Save your "Game Details" changes.
Click on Linked Apps tab (Game Services -> Your App), select Android Platform, fill in the package name, save and authorize.
This takes you to create an OAuth Client ID. Follow the steps here to create the SHA finger print.
Save your Application ID (See the number next to your project name) which will be used in NPSettings for Sign-in.
Make sure you use right keystore for generating the SHA fingerprint.
Creating Achievements 1. Under Game Services tab -> your selected application, select Achievements. 2. Create Achievements and note down the identifiers.
Incremental achievements are those which takes multiple steps to complete. Rest of the achievements unlock with one step.
Under Game Services tab -> your selected application, select Leaderboards.
Create Leaderboards and note down the identifiers.