A campaign represents the notification, campaigns can be saved, modified, deleted and sent every time you want.
In section Campaigns > New Campaign you will access to campaign creation form where also you can see a preview of the notification in a real device.
In the top of screen you will the target platforms of the campaign and the campaign name.
The configuration of the campaign is divided in 3 tabs:
At the bottom of the page you will see a number of device that will receive the notification or if the campaign will be sent automatically. Also you will see the actions of the form, save and send the campaign or just save for sending it later.