I have a Mac Pro 3,1, which came without a hard drive.
Now I want to install macOS El Capitan on a new SSD in this machine. I started creating a USB-Stick with El Capitan on it.
I used this link: https://itunes.apple.com/app/os-x-el-capitan/id1147835434?mt=12 which leads me to the App Store. But if I click on download, it says that it can't install macOS on my hard drive because the system is too new. The system I used to do this is my Mac mini 5,1 with Sierra.
How can I create, with this Mac mini, a USB Stick with El Capitan setup for my old Mac Pro?