The notification icon is present in the bottom right on every page in Maximus.
When there is a new notification, the icon will update displaying the amount of unread notifications. Clicking on the icon opens the notification drawer that displays all notifications.
Clicking on the campaign name redirects you to the campaign details page for that campaign.
To mark all notifications as read, click Mark All As Read.
To disable notifications, click Settings -> User Settings -> User Preferences. Click here to learn more about the Settings page. From here, click the toggle and click submit.