first time installing it–doesn't open–please help

This is my first time installing it. I have FTP all files into my web server and have edited the wp-config.php file to reflect the database, host, password etc as shown in my Cpanel. I thought that was the only thing I needed to do. When I type my web address, I get the forbidden messange on the browser. What I am missing? Is there anything else beside modifying the wp-config file?
Please advise