How do I install Mac OS X El Capitan on my other iMac? [duplicate]

I'm relatively new to Mac and I cannot for the life of me figure out why it is so complicated to download an OS installer, create a bootable disk and use it on another machine.

According to the official Apple documentation here, one must:

El Capitan downloads as a disk image. On a Mac that is compatible with El Capitan, open the disk image and run the installer within, named InstallMacOSX.pkg. It installs an app named Install OS X El Capitan into your Applications folder. You will create the bootable installer from this app, not from the disk image or .pkg installer.

I downloaded the 6 GB file. But when I run the installer, I get a message saying

This version of OS X 10.11 cannot be installed on this computer.

But I am not trying to install it on this computer! I want to install it on a different computer!

How do I just get the OS image so I can create the bootable drive to use in the other machine?

I really appreciate your advice!

Solution 1:

Given that you have the IntallMacOSX.pkg file you need to extract the app -so, you want this answer: How can I open a .pkg file manually?

You can then extract the "Install OS X El Capitan.app" application into your Applications directory and proceed with the steps as outlined by Apple.

Solution 2:

I moved this answer to earlier duplicate question.