Okay, that might be a stupid question, which it probably is. I apologise in advance, but I couldn't find answer to it in the manual. I hava a website basis that I've already uploaded, but I cannot access any of the pages on it - when I go to http://studentunion.trap17.com/ I get the screen with congradulations, not my starting page, although I followed the instructions on the page. When I manually try to access the index.php file through the address bar - it says that the file does not exist although I gave all the necessary permissions for anyone to view it. How can I do that?

The site Index file MUST be placed into the public_html or www folder. If it is in the "account root folder" it will not be accessible from the Internet.
Upload it again or use Cpanel to move it into the correct folder.