In order to start creating schema markup for another domain, we recommend creating a new project. To create a project, go to your Schema App homepage, click on “New Project”, fill in the name, and click “Create”. 

If you don’t see the “New Project '' button, you may see one that says “Upgrade for more projects”. This is because adding multiple projects requires a subscription level of ProMultiSite or higher. You can learn more about pricing and plans here