If you have more than one listing, you will have the "All Listings" listing group under the "Messaging" menu. You will also see the Listing groups you have created in that menu. You will also see a list of your individual listings. You can make a message rule for "All Listings", a listing group, or an individual listing.
The reason we have a few places to create messages is to help save you time. Here is an example of how you save time by making rules in different places:
I have 5 different listings that I manage. Two of the listings are in the same town and use the same cleaner. I made a group for these two listings called "Austin".
The messages that go to ALL of my guests I created in "All Listings". This includes the message that checks in on the guest and asks them if they need anything, and the message asking for a review.
The messages that go to all of my Austin listings are created in the "Austin" group. This includes all the messages to the cleaner (new cleaning, cleaning change, cleaning cancellation, and reminders), and my message asking guests to take out trash on a specific day of the week.
The messages that are specific to each listing are created under each listing. This includes the check-in instructions that are specific to that listing.