On Student Dashboard, every assignment has three statuses which will display to your teacher. By default, when you are sent a new assignment, this status will be set to 'Not Started'.
When you begin to work on your assignment, you should change this status to 'In Progress'. This will let your teacher know that you have started your assignment and so they can be ready for any further actions they may need to take.
Once you are happy with your assignment and you need it to be collected by your teacher, change this status to 'Complete'. Your teacher will then know that you have submitted files as part of your response, which they can collect and then provide you with feedback.