Discord's Community features rely on three designated channels: the Rules channel, the Community updates channel Discord posts admin notices to, and the Safety alerts channel where raid warnings land. Point each one at a channel by name and Packet keeps the designation attached to it, so renaming, moving, or replacing that channel doesn't quietly break the pointer. All three have to be text channels, and the editor warns you if one isn't. Discord wants Community set up before announcement channels, stage channels, and the onboarding wizard below are available at all. (Configure → Community.)
Tick Enable Community, then fill in the Rules channel, the Community updates channel and the Safety alerts channel. Packet checks these when you save and tells you which one is still missing. The welcome screen needs Community too. Turning Community off later also turns off onboarding and the welcome screen in Discord, so the apply asks you to type a confirmation before it does.