Click on the pencil icon to access the Button Settings. You can also use images, or any other element to trigger the filtering. It doesn’t have to be a button module.
Go to Advanced → CSS Class. Here you add the ef-button class.
Additionally add any category that you want to filter with that button like that: efc-[your category] e.g. efc-cats.
Section:
Click on blue gear icon to access the Section Settings.
Go to Advanced → CSS Class. Here you add the ef-area class.
Columns:
Click on edit column icon to access the column settings.
Go to Advanced → CSS Class.
Here you add all the efc-[your category] class you want e.g. your efc-cats class.
Do that for all Columns you want to make filterable.