This short snippet explains how to boot from an installation medium on a Mac. The installation process itself is extensively documented for most operating systems. However most modern Macs require some additional steps to even get to the point of running a live DVD, especially if you do not have access to an original Apple keyboard. This snippet documents this process.
This process is well documented. One way of creating a bootable medium is to use balenaEtcher. Install via Homebrew:
brew cask install balenaetcher