I see all kinds of instructions online that say how to make a boot disk that installs El Capitan. I just want to start my computer from an external disk -- I am not trying to do a clean install. Is the procedure the same? Will the bootable install disk just startup as normal if I tell it I don't want to reinstall the system somehow?
It's just that all the instructions seem to assume you want to do a clean install, and that isn't what I am after.