Log into your Canvas Course and click "Grades."
First, it is important to note that all modules with graded assignments must be published (even those from the past). If you unpublish a module, it will override the publishing of an assignment. You can still adjust your "available to and available from dates" to keep your students from viewing or editing any assignment you create.
At the top of the gradebook, make sure that 1) all 3 items are checked under "filters" 2) all grading periods are selected 3) all modules are selected and 4) you can either show all sections or an individual class setting. You will then be able to see all assignments!
After doing both of these things, all assignments will show!
Thanks,
Maggie