I have a 2006 Mac Pro (MacPro 1,1) with 4GB RAM running OS X Lion (10.7.5)
I've been using this link: https://support.apple.com/en-us/HT210717, to try and upgrade my computer. I've successfully downloaded the file (InstallMacOSX.dmg) from step 4, but whenever I try to open the file to install it onto my computer, my computer tells me that it can't read it due to it not being recognizable.
I've tried using disk utility to open it via Image>Verify, but it still didn't open it for the same reason. What can I do?