Please continue reading the docs. After installation you are supposed to create a configuration for every node type (all but the first node must contain the server url and the cluster token) and put it into /etc/rancher/rke2/config.yaml (or into a config.d directory at the same place). If you don't do that, you'll create a single node cluster with all default settings. After placing the config onto the node, you enable and start either rke2-server or rke2-agent service (e.g. systemctl enable --now rke2-server on a master node). Imho the documentation about how to create a config.yaml is really bad. It just explains the options, but not how to generate a yaml from it. There are pretty good video tutorials in the Rancher academy to get started.