Hello there, @saraghezzi 
If you are an instructor and see the crossed-out eye icon next to the "Conferences" course navigation button, that means it is hidden. You can enable this button via your course "Settings" screen. How do I manage Course Navigation links? Then, you can review this short video tutorial on how to use "Conferences": . There are a handful of written Guides that are also available if you want to take a deeper dive into the inner workings of Conferences.
If you are a student and the "Conferences" button is not visible in your course, you will need to contact your instructor to ask him/her to enable that button so that you and your classmates have access to it. How do I get help with Canvas as a student? This Guide has instructions on how to contact your instructor directly.
I hope these resources will be of help to you, Sara. Sing out if you have any other questions about this. Be well...stay safe.
