How do I navigate to my course's Quiz Library and/or create a custom link for quick access?  

1.  Click on  Assessments–>Quizzes
2. Click on Question Library from header (look in between Manage Quizzes and Statistics).

Brightspace Tip

If you want quick access to Question Library, create a custom link:

1. Go to Question Library and copy the URL from the toolbar.
2. Create a module and label it Question Library and then change it to draft.
3. Inside the module, create a link and paste in the URL from step 1.  Try both ways as external or within to see what you like in terms of space.