Install routerd for a first lab
The authoritative installation and upgrade instructions are in Install and upgrade. This short page exists so a reader following the tutorial list reaches that one source of truth.
For a first experiment, choose an isolated Ubuntu Server VM or a spare computer with console access. Ubuntu Server is the primary target. FreeBSD and NixOS are second-tier groundwork and should not be the first platform you use to learn the workflow.
After installation, continue in this order:
Do not run a live apply over the only SSH connection to a router. The install page explains how to validate and dry-run a file before starting the service.