So you've unzipped the folder correct? (Using winzip or your basic comuter software, depending on what your running on)
If you've connected correctly in to your FTP, you should see all your files and directories, etc. If you're having problems connecting to your FTP, what exactly aren't you getting? Do you have the correct username/password/host etc? Or is it something else?
It should be public_html > wp-content > themes
If you've done all that, check inside the folder on your computer. Sometimes I'll have downloaded themes and it won't directly be the theme files inside. Instead it will be something like 'amazing_grace', and then inside that another directory called 'amazinggrace' and a readme file or something. This like this vary, but I guess what I'm trying to say is make sure your uploading the directory with the wp files in it like index.php, header.php, page.php, etc.