On AutoProctor, an Unsubmitted test is one where the user doesn't click on the Green Submit button at the top of the test. That is, the test taker has started the test, possibly seen the questions, but hasn't submitted the test.
To view Unsubmitted tests, you can click on the checkbox that says Unsubmitted Tests on your Test Report page. When you click on the Checkbox, if there are unsubmitted tests, you should see them listed on the page.
If you are conducting a Proctored test, when you visit the Test Attempt Report of a particular student, if the student has Unsubmitted Tests, you should see a button that tells you how many such attempts were there. For example, the student below has 5 Unsubmitted Test Attempts. You can click on the button to view these results too.