Once registered you will be presented with the main workspace called the "Message List".

This lists all AVAILABLE messages that have been posted for your attention, acknowledgement or actioning.

Messages will appear in the List until they are actioned or expire;  in both scenarios the message will then be moved to Message History ( See History ) and remain there for 30 days (max.) before being purged automatically by the system.  

Note also, for security, that the Message List data is cleared either when the user de-registers or if the APP is uninstalled.