You can use File Manager to upload files to your web site, up to 12 files in one go. Although useful, a third-party FTP client has many more features and does not limit you to the number of files...

You should upload your website files into the public_html folder.

You should upload the files that form your website content into the WWW folder or the public_html folder. Those are the folders where you should put your website files and content in.

WebPages and files should be uploaded to the directory called 'public_html'. Anything you place in this directory will be accessible from the web at the root level of your domain.