PostNuke may be a little different, but close, based on your instructions.
First, make sure that MySQL is working and that you have root access to it (that's a different issue).
Then, unpack the Postnuke distribution. The simplest way is to unpack it in your document root, i.e. /var/htdocs
"tar -xfvz PostNuke-0.726"
Then you'll have /var/htdocs/PostNuke-0.726, with "html" and "phoenix-sql" directories under it. My preference is to then make a link in the document root pointing to the html directory:
"ln -s PostNuke-0.726/html nuke" (in your document root).
Finally, point your browser to
and follow the directions. There is a checkbox in this script to create the database, if needed. My preference is to create it manually before running the script:
mysql> create database Phoenix;
mysql> grant all on Phoenix to nukeuser@localhost identified by 'foo';
Then specify this user when asked by the install.php script and leave the "create database" checkbox blank.