Push Notifications are provided by a 3rd Party called Pusher. It's free to use for up to 2000 users/devices when sending notifications to the users.
Please go to the Pusher Website and create a free account.
In your Pusher dashboard click on Get Started under Beams
Give a name to your instance
Skip the following step
In your Pusher dashboard click on Keys on the left menu and copy the instance ID and Primary Key
Then go to your Rovbots Chat dashboard>Settings>Notification>Push Notifications and paste these keys.