Unable to install OS X El Capitan on new hard drive (Early 2008 Mac Pro)

thank you... this process is unnecessarily complicated mostly due to the fact that the documentation is not clear at all about this. for one, you are not downloading the El Capitan installer from the El Capitan installer link. you are downloading the installer for the el capital installer. thank you for providing that insight or I would have been stuck for a while!

it is also not documented anywhere that I saw, that the installer for the El Capitan installer could not be installed on the target drive for whatever reason, but had to be installed on my active startup drive. this is a little counterintuitive since I was trying to install El Capitan on a different drive. so naturally one would assume they could install something called the El Capitan installer on that target drive.

I love yo apple but it would be nice if you could provide better (clearer) step by step instructions about this!

thank you for your response!! those are the links from which I had downloaded the installer. I was also following the instructions found at the second link. the problem is, even in the instructions, the title of step 4 is "Download OS X El Capitan" when you are actually downloading something 2 degrees of separation from OS X El Capitan, namely, the installer that installs the installer for OS X El Capitan. similarly, step 5 is titled "Install the Mac OS Installer" when you are actually installing the installer that then installs the Mac OS X installer. So again the instructions are VERY misleading. So naturally, when I wanted to install it on a spare drive, I attempted to install it there but it appears that the installer installer cannot be deployed that way, hence the grayed out drive when trying to specify where to install the software. Even the dialog window when I tried to install the downloaded installer said, "Select the disk where you want to install the OS X software." The disk I wanted to install it on was the "Untitled" disk, but the dialog should have said "Select the disk where you would like to launch the installer software that will in turn install the OS X software (Note: the location to install the installer software that will install OS X cannot be on the target disk for the OS X software itself)". Very strange Apple!!

but thank you HWTech for the speedy reply and the helpful links ;-)

thanks eau rouge,

i think i was already a little annoyed with the process because i had a previous version of the "Install OS X El Capitan.app" on my startup drive (probably from when the computer itself was originally upgraded to El Capitan) that i was attempting to use but after going through the install process several times, each one of which took about 30 minutes, before getting an error message that the software could not be installed (i forget the exact error message itself... something to the effect of no valid packages found or something?). So i think that must have just been a corrupted version of the installer? I downloaded a fresh copy of the installer for the install app and that is when i arrived at the point that lead to my original post here. Thanks to your reply and that of HWTech I realized that it was not asking me where i wanted to install OS X but only where i wanted to install the installer... after that realization it was easy and the newly installed installer app worked fine.

Simply following the Apple instructions would work fine if you were upgrading the startup drive, but there should be some sort of note at the beginning for the option you want to install on another drive... that doesn't seem like such a remote possibility.

on a different note, i participate on other user forums (for filemaker pro, or adobe photoshop, for example) and on occasion a tech or support person from one of those companies will post a reply. Does that not ever happen on this forum?

thanks again for your help! :-)

thanks again for all the help... without a little guidance i would still be pulling my hair out now!

i admire the depth and breadth of your knowledge on the topic and greatly appreciate your willingness (and that of HWTEch) to make the effort and take the time to help me out :-)