In Rancher, install the elemental UI extension and the elemental operator into the local cluster. See https://elemental.docs.rancher.com/next/rancher-vmware/#part-1-rancher-configuration
Create a machine registration endpoint with the defaults and Download the registration endpoint file.
On an intel mac or some x86 vm (I used the AWS VM where Rancher is running on):
Download the iso generation script
wget -q https://raw.githubusercontent.com/rancher/elemental/main/.github/elemental-iso-add-registration && chmod +x elemental-iso-add-registration