Using this method, You can upload any file or folder via FTP.
Here, in this tutorial, you will find a step by step guide how to install a WordPress theme (or plugin) via FTP.
Step by step guide…
Create a FTP account
Download and install Filezilla
Connect FTP via FileZilla
Upload your theme files to wp-content/themes/
or upload your plugin folder to wp-content/plugin/
Download FileZilla free here;