I've installed Tidio on Brewquets and disabled Messenger.
Currently I have it running from 9AM to 6.30PM in terms of availability but this can be changed if need be. Weekends entirely offline. You can also easily go online / offline / scheduled times easily by clicking on your avatar in top right. DND is the Do Not Disturb schedule that is set to be offline for set times.
People receive a "welcome" message telling them we are there to help upon their first visit to the site.
There is an app you can download from app store and there is also a desktop app you can download from the site when you log in, go to the Home icon.
The website to log into to manage everything is https://www.tidiochat.com/
Log in details you should be able to access from last pass.
Any Offline enquiries goes to [email protected] address.