Moderation is where your team records problems with players in your game (not staff), decides what to do, and carries out warnings, kicks and bans. The decisions are then enforced in your Roblox game by a small module.
The parts
Cases: a record about one player: the reason, internal notes, evidence and the action decided.
Actions: Warning, Kick, Temporary ban or Permanent ban.
Evidence: pictures, videos or links that back up the case.
The in-game module: a script in your game that reads punishments from Rosterr and enforces them.
Logs: every step is recorded.
Switch it on
Open Settings > Features and turn on Moderation.
Open the Moderation settings there. It says: "Install the moderation module in your Roblox experience to sync bans/kicks in-game." Choose Download module.
Add the module to your game in ServerScriptService, and make sure Allow HTTP Requests is on in Game Settings > Security.
Give your moderators the permissions they need (see below).
Without the module, cases are only a record: nothing is enforced in the game.
What the module does
It asks Rosterr for new punishments about every 15 seconds, and also listens for instant messages so bans and kicks apply quickly.
A kicked player sees "You have been kicked from this experience." A banned player sees "You are banned from this experience." These messages can be changed in the module's settings.
The module can show an appeal message to banned players (for example where to appeal). This is off by default. If you turn it on, change the message in the module's settings to your own wording.
A punishment can apply to all places in your group's games, or only specific places you choose when making the case.
The module uses an API key made for it, built into the file you download. Download a new one if you need to replace it.
Permissions
See "Permission reference (3 of 4): moderation, alliances, docs, policies and applications". The main ones are View moderation, Create moderation cases, Edit moderation cases, Execute punishments (kicks), Execute bans, Revoke punishments, Upload evidence and Delete evidence. Use the Moderator preset as a starting point.
Related articles
Open a moderation case (and what each field means)
Evidence: what you can attach to a case and how it is checked
Execute, revoke or delete a punishment