In settings you can set your email/SMS limts, campaign groups and your notification API keys
Campaign Policy defines a period of time before a customer can receive another message of the same type. You can use different policies with different scenarios.
Campaign group define a category of emails / SMS from which customer can unsubscribe separately.
Campaigns Policy and Campaigns Groups are applied only to emails and SMS
Here you can set default email sender and if you use mailgun for sending emails you can set here your account
Set your Google Cloud Messaging API Key and Apple Push Notifications Certificate