Your question seems a bit vague. I assume you already have Apache set up and running, and you've added a call to mod-php in httpd.conf (or you may have an /etc/httpd/modules.d or similar; I don't know PCLinuxOS specifically).
Assuming all of this, you can simply put .php files in your webroot (possibly something like /var/www/html/ or /var/www/html/htdocs) and put PHP code in them. Then, when you visit that webpage (i.e.
http://localhost/test.php) anything inside of a <?php ?> tag will get interpreted by PHP.
