After you grade a submission, the grade is now on hold until you choose to release it. From the submissions tab, you can filter by "NEEDS TO BE RELEASED" on the right-hand side and select all or specific students. From the Bulk Actions section, choose "Release Grades".
You will be presented with a modal to confirm that you want to release the grades. The student will be notified that their submission has been graded via email which contains a link to their submission granting them access to any manual grading and and hidden test cases depending on your settings. Any feedback you may have left on assignments will also be visible. (Feedback on projects continues to be delivered to students within 30 minutes).
If you want to read more about coursework statuses and what the mean you can find that information here.