Serkan Bekiroğulları, if I understand you correctly you can't see the Upload video button on the list video page. You can manage to hide/display this button by the Roles settings.
So, first of all check the Roles settings. Go to the Admin Area> Privacy&Permissions> Roles section and make sure that the "View video" option is enabled to all roles you need.
If you did it and still have the problem try to deactivate all third-party plugins and check if the issue persists.
If you did all of these steps and still have the problem try to set the default Origin theme.