Notifications can be set with the bell setting at each channel or room. Some preferences can be set in the Personel Settings dialog. Receiving unread messages must be set, to receive notifications.
When starting Rocket.Chat, you are asked to allow desktop notifications. Notifications appear as small boxes on the right corner, depending on the general or per room settings.
Depending on your settings per room or channel, you receive notifications on your mobile device for all messages or only, if you are being mentioned. Notifications in rooms are only sent of you have not been using the desktop client for more than five minutes. Currently, changing your status to "Away" does not speed up the countdown.
Depending on the privacy settings set by the administrator, you will see the sender, room name or the first line of the message as a notification on your mobile device.
Notifications of direct messages to you or if you are mentioned by @username are sent by Email to your E-Mail address, but only if no web-client is connected.
@username - notify this person @all - notify all members of this room or channel @here - notify all members of this room or channel who are online