Never try uploading a folder (directory) using the cPanel upload mechanism. It will just sit there at 0% complete forever and you’ll think there’s something wrong with your connection. The easy way to update a website is to compress the whole thing, or at least the bits you want to update, into a single ‘.zip’ file, then upload that. Once it’s been uploaded, simply unzip the contents of the ‘.zip’ file into the ‘public_html’ folder, remembering to tick the box that says ‘overwrite existing files’. Your updated website will then be visible to the world, i.e. published.