Hey Dawn,
Your link http://seo-developer.com/ opens a WordPress hosted site. That means WP is already installed on your GoDaddy hosting...
You must have got your WP username and password to log in and make changes you wish.
-- By the way one of the best ways to upload a file to your server is ftp or sftp. You can use clients like cyberduck or filezilla to upload/modify files using ftp/sftp