When you sign in to your account via an FTP client (Filezilla, CuteFTP, FTPExpert), you get to the root of your hosting account.

Here's what you should see when connecting to your FTP account

/ Access-logs
/ etc
/ mail
/ public_ftp
/ public_html
/ tmp
/ www

This is the root of your site and all of its directories contains important data for the proper functioning of your account.

In what directory do I place my site?

You must upload your documents to the "public_html" folder that says it by name, HTML is made public. After that, your visitors will be able to see the content of your website.

Note: The starting file of a website should always have the following name (s): index.html, index.htm, index.php. This will be your first page visible to the visitor.