Website won't upload

I'm new to this sorry in advance if I'm asking a silly question!
I joined a web hosting site they have asked me to upload my website into the public_html folder and to make sure it's called index.html I have done all of this and my web page is in the public_html folder but the website doesn't show at all, when I go onto my website I still get the "welcome to your new hosting package" page.
What am I doing wrong?
Thank you so much for any help you can provide :D

Just wondered if you found a solution to the above as we have a similar issue with a client server...?