How to set arbitrary values ​​​​in the 1s-Bitrix smart filter?

Question

1C-Bitrix

The task is to supplement the smart catalog filter with a new "busy" filter. I have such a field "employment" in which a string of different types is stored: "Free", "Busy until 05/31/2018", "Booked", etc.
I need to display only two values ​​in the filter: "Free" and "Employed". Accordingly, those that have the "Free" values ​​refer to the "Free" filter value, and all the rest - to the "Busy" filter value.
I've added an "Employment" field to the smart filter, but the dropdown is empty. How can I supplement it with two options and write a selection condition?
Thank you!

Answer 1

Shop - Main catalog of goods - Catalog settings - Properties of elements
there you mark your fields.
You write the selection condition directly in the template. You catch saints, you hide Booked. When you click on the field Busy Booked you make cheked.