You can configure Slack notifications on the account, team and project level.
After you've connected your Flare account to Slack, you can specify in which Slack channel the Flare notifications should be sent. When you specified a channel you can send a test message by clicking "Send test notification".
Here's an example of a notification that gets sent to Slack. Notice that at the bottom of the notification there are buttons that allow you to resolve and snooze the error right from Slack.