To find the inbox in the app, there is an icon on the bottom that illustrates a list. The inbox list every registration in the project. To be able to find what you are looking for, there is a sort functionality in the top left corner (two arrows pointing up and down).
These are the things you can use sort on:
Due date/Deadline: Using this as sorting, you will have the registrations with oldest due date/deadline date on top. This way you can easily do the most important ones first.
Date created (newest): Here you will have the lates created on top.
Date created (oldest): Here you will have the easiest created on top.