Please make sure you have uploaded the files correctly on the root folder of your website.
If the root folder is public_html, there should be many files when you open that folder, like index.php, init.php ..... and folders like classes, install, config, controllers
There should not be just just one folder called 'prestashop'.
And if those files are there and uploaded correctly, try to open your website like this www.vinobirraliquore.it/install