Okay, if you login to your cpanel, you will see a page if you look, there will be something that says "File Manager" Click that, once you have pressed it, it will ask you what directory you want to go to, select public_html and press okay, it will then load the public_html directory and all its files, you will then see a webpage (the default homepage) called index.html, when you want to upload your own homepage, you should press the upload button at the top of the page, tick the box that says "Overwrite existing files" and then upload your own index.html and all your other files you need.
If you don't understand, or need more help, just ask.
Go in cpanel in the file manager and you'll see in the header a upload button, upload your site in a .zip file and extract it where you want, and you can start working, or use a ftp like FileZilla and set in your information and connect. Its easy. If you need help. Pm me. Ill respond fast as possible.