The assignment has been released. That means that your students can see the assignment on their dashboard now.
The assignment has been assigned to a class, but it has not been released yet.
This indicates that one or more students (number of hand-in = number shown) have handed in their assignment. You can start .giving feedback now. Click on the number or on the assignment. You will find yourself in the Workflow where you scroll down to the student(s) that have handed it and click on→ Feedback.
This only applies if you have an extended deadline (for more see here). In that case, you can send your students a reminder once the deadline has passed. Click on → the assignment and afterwards on → Reminder in the Workflow. The students will receive an email that will remind them of their task.
You corrected all the assignments that your students handed in. No work is required from your side anymore.
You completed your feedback for one or more students (these students are in the “Ready” state) but you have not sent the feedback to your students yet. Click on the circle (you will find yourself in the Workflow) and afterwards on → Release all under Feedback. Now you can select if you want to send the feedback to all students or only to some of them.