Harry You get notifications via push notification to your mobile phone (and certain notifications via e-mail).
If there are any unread notifications when you open the app, then there will be a yellow banner on the Home tab under the three circles and above your sub-accounts.
If you have messages from Support, they can be found under Profile > Settings (top right) > Need help? Get Support (at the bottom) > Announcements or choose the chat that you're interested in.