if you use yum to install the packages, then you only need to edit the httpd.conf file, normally stored in /etc/httpd/conf/
there, you only need to set server name and the server admin email address, apache will be configured to run by tthe installer.
read where the "Documentroot" is in that file, and that is where to put the pages for the server.
fire up the system services control tool, and make sure that mysql and httpd are set to start at boot time in the default runlevel
with yum, install mod_php to have php support in apache, before you start editing the httpd.conf.
you don't need to manually download anything, you tell yum what to install and it will get it for you.
it will also get the requirements for the packages so that you have everything needed.