Go to the Filters tab and press the green plus button.

Enter filters title and choose the attribute, which will be used for filtering.

For example, we’ve created filter that is called “Dog food” and based on the product type.

Next, you need to add values (product types in our case) for your filter. Click the green plus button.

Add the necessary product types for the filtering.

Please don’t forget to click the ADD VALUES button after you choose the values.

All values can be edited after you add them.

Note: these values aren't excluded from the standard filters!

Now, we have our own filter “Dog food” on the Search results page.