Hi Carl C,
I'm Femi and I'd be happy to help you with your question.
Just for clarification, you meant that the multi-level list doesnt appear in the tab at all. Kindly attach a screenshot so as to get a clearer understanding. In the meantime, you can try this: Click in the first Heading 1 paragraph of the document and then click Home | Multilevel List | Define New Multilevel List. In the dialog box, click level 3 and clear the content of the "Enter formatting for number" box. Recreate the numbering for the current level and add levels 1 and 2. Type in the separators (periods) between the numbers. Also, verify that the levels are properly associated with the heading styles (Heading 1 for level 1, Heading 2 for level 2, etc.). Source: https://answers.microsoft.com/thread/cda37bcc-e2b9-44d1-a870-8826eef7e3a8
Best Regards,
Femi