Unfortunately we don't have access to your particular Canvas instance but it sounds like your instructor did not make the Assignments link available on your course navigation. You instructor might have linked the assignment on a page or module or even on the Syllabus.
Also on your dashboard you can look under To Do and see if the assignment is listed there or you can click on the three dots and switch to List View to find the assignemnt.
Last suggestion would be to reach out to your instructor and let the know you are having issues locating your assignments.
Hope this helps you and good luck.