You can add a Call-To-Action button in your Facebook page which will link to your campaign by following below steps:
1. Open Facebook and go to your Facebook page.
Note: please sign in with the account which can manage your Facebook page.
2. Select “Add a Button” button.
3. Select “Play Game” option.
4. Input the campaign URL which given to you after publishing the campaign.
5. It’s done, a Call-To-Action button, which will link to your campaign, has been added to your Facebook page.
Tips: You can use another account to access your page and test this new button.