Hello,
Are you sure that the update needs to be done on your production site? Some styling will be changed and we do not remember how looks all elements on your site. It would be better for you to create the full copy of your site.
To make the update we need FTP access (FTP hostname, FTP username, FTP password) also. Please ask your hosting provider support to create FTP account to your site files and give us the credentials.
Regards