Two kinds: run a command inside your site, or call a URL on a timer down to the second
Open Cron jobs → New job. Pick the site, name it, choose a schedule and enter the command. It runs in that site's folder as that site's user and cannot reach anything else.
logs/cron-<id>.log — the “Output” button shows it.Open Cron jobs S → Add job. Name it, choose the interval (seconds / minutes / hours) and give the full URL. It starts immediately and can be paused or deleted at any time.