Hi @0608038186 and welcome to the Community! You cannot see your dashboard at all or you cannot see your courses on your dashboard? If you can see the dashboard tab but there are no classes there, it could be because your instructor has not published the course. You could contact someone at your school's support group or Canvas Support and they would be able to look at your account and see if this is the case. If you log in to Canvas and cannot see the dashboard tab at all, I would probably suggest contact Canvas Support (options under question mark icon) to see if they have any suggestions.
Does this help? Is it just your classes you cannot see at this time?
All the best!