To access your Progress section, tap the navigation button on the top left to locate Progress in the navigation menu.
As a teacher, after selecting Progress, you'll see see that you can sort your Assignments on Edmodo from three different views - Groups, Assignments, and Students - allowing you to easily find what you're looking for as well as drill down to a specific student and see all their work in one place. Once you select an Assignment, you will see numbers on how many students still need to submit the Assignment, as well as the Assignment itself (the text and attachments you originally sent out on Edmodo). Below, you will see a list of all recipients of the Assignment, and can tap on an individual student to see their submission.
If you select a Group, you will then see all Assignments sent to that Group.
From a student's submission page, you can view their work as well as add a grade and leave a comment.