Download El Capitan Installer now that Sierra is out I have recently been having issues with my mac and want to do a clean install. I still have Yosemite and thought it’s a good time to upgrade the OS. However, I am wary of jumping directly to Sierra when it’s so fresh.

My specific circumstances: 


Sierra could run on my computer (early 2015 Macbook Pro), but I would prefer to install El Capitan
I have not previously downloaded the El Capitan installer


I realize apple provided a link to install El Capitan from Snow Leopard. However, when I follow the links to the app store to get the install file, I am met with this message:


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


Is there a way to download the El Capitan installer now that Sierra is out, for more modern computer? Searching El Capitan on the app store yields no results for the installer.
It depends on your circumstances. It can be difficult to find old OS downloads.

If you purchased it previously it will be in the App Store under the Purchased tab. 

If your mac came with it pre-installed you may have to go the internet recovery or Recovery HD route, but that would entail wiping your hard drive in order to do the install. You could then migrate your user data from a Time Machine backup or similar. 

Alternatively, if you have a bootable backup of your El Cap system (assuming you had it installed) you could reinstall that. 

More specific answers will require more specific information from you (it's generally a good idea/helpful to provide more information so that answers can be geared towards your situation and others in the same situation can benefit). 

Whatever you do, make sure you have a full working backup (which you have tested) so that you can revert should something fail.