Hi @meryemjabrane,
The left hand menu (course navigation) is configured for the entire course. It could be possible to hide menu items from certain sections with custom css/javascript set up in an account/subaccount theme, but you'd need to speak to your local Canvas administrator(s) about that. As a Canvas administrator for a higher-ed institution myself, I can tell you that our team here would very likely turn down the request because of the custom work and maintenance it would require. Your team could feel differently though, so it's always worth asking.
-Chris
