You can choose to receive a Push Notification when a user follows you, likes or comments on your artwork, or sends you a message.
At the moment, Push Notifications are only available on Android.
To adjust your push notifications, from the menu on the bottom right:
Click More > Settings > Notifications > Push Notifications
From here, you will have the option to adjust which kind of push notifications you will receive or not. By default, they are all enabled.
If you can't see the Push Notifications option, please make sure that you have the latest version of the app.