To download and SAVE the installer, you first need an 8GB or larger USB-stick. Name it exactly MyVolume
Download El Capitan as if you were going to re-Install. When the Installer starts, cancel it and use this article. Cut and paste the appropriate command directly from the article, and paste them into Terminal. If you named your USB-stick MyVolume they work without any changes.
It typically takes 20 to 30 minutes to actually write the USB-stick, which will feel like an eternity because it does not give you ANY feedback during that time:
How to create a bootable installer for macOS - Apple Support
The bootable USB-stick Installer takes the place of a DVD. It is bootable, so you need nothing else. it has the Utilities in it. it has the Installer image, so you can get most stuff Installed..
You could conceivably Create a DVD using a process very similar to this one, but a DVD is so slow, it would take an hour to write the DVD and nearly half an hour for the DVD to boot up, before starting the Install. The USB-stick method is superior because it is MUCH faster than a DVD.