What is a master-sub property set up in Hostfully? Please refer to this article: Managing calendars for a house and its sub-units
Step 1: Create a Booking.com account, property listing, (optional) room types, and enable Hostfully as the Channel Manager
Booking.com admin account page: https://admin.booking.com/
One listing or multiple listings? It depends on your tax rate and cleaning fee.
Only one tax rate and cleaning fee can be applied to one Booking.com listing. If your master and sub properties have different tax rates and cleaning fees, and you want to keep them that way on Booking.com, you'll need to create separate Booking.com listings in your account in - one listing per property - and continue to Step 2.
If you'd like to list both the whole house and the individual rooms on one Booking.com listing, for example: in Hostfully you have 5 properties: the whole house is Hotel Malibu, and the individual rooms are Room One, Room Two, etc... , on Booking.com you'll need to have 1 property listing for the whole house Hotel Malibu. On this property listing, create 6 room types - 5 for the individual rooms and 1 for the whole house Hotel Malibu.
Finallly, enable Hostfully as your Channel Manager. Please see the following article on getting this set up.
Step 2: Unlink the master-sub properties in Hostfully
Defining the relationship between booking entities is the first step. We covered the step in this article "Managing calendars for a house and its sub-units". You'll need to unlink them to map to Booking.com before linking them again.
Step 3: Map to Booking.com property and room types
Go to Channels > Booking.com (Manage this channel) > click OFF to toggle it on. the the. You'll see the pop-up window below. Enter the Hotel ID provided by Booking.com for your hotel, and click Connect:
It will then ask for the Room type ID. It is the ID found under the room type name in your Booking.com Extranet > Property > Property Layout. Copy this code to Hostfully and proceed with the Rate as the "Standard Rate" or "Hostfully Rate". Finally, click Connect. until it says Success.
Step 4: Link the master-sub in Hostfully again
From that point on, your sub-units will be synchronized with Booking.com's units and your calendar/prices/property data will automatically synchronize.