Cron triggers manual or automatic?

when my bot joins a server will the cron trigger start 1 hour, 1 day, 1 week after? do i need to do it manually? can i trigger it through a command?

Crons triggers are not executed on a per server basis, nor do they execute within the scope of a server. They will always execute at their specified time within the UTC timezone as long as the flow is enabled (which they are by default and can only be disabled from the flow editor). For example, the every day trigger will execute at 00:00 UTC every day