For students
Your results
Submitting is not the same as being marked, and being marked is not the same as being told. Your teacher decides when a result reaches you.
As soon as you submit
Some assessments show your result the moment you hand in. You find out where you stand while the questions are still fresh.
Good for practice, and anything you are meant to try more than once.
When your teacher releases them
Others hold results until your teacher is ready, usually once everybody has finished.
Good for work everybody sits at a different time.
If nothing has appeared, that is the usual reason. The marking may be done and simply not released yet.
What you get back
Your teacher chooses between a mark, their comments, or both. If you get comments with no mark, your teacher chose that. They want you to read the feedback.
Programs are often marked by running them against test cases the teacher wrote, so a result can tell you which cases passed and which did not.
Asking for another look
If you think a mark is wrong, you can ask for your answers to be looked at again. Your teacher is told you have asked, and your marks stay exactly as they are until they decide.
Asking does not change anything by itself, and it does not reopen the assessment. You are asking a person to look, not undoing your submission.
What next
The work continues in the editor. Anything your teacher shares with you turns up in your projects, whether or not it is being marked.