Hello,

The filter will work with variable products, which has various attributes to filter. If you have not variable products. The filter has nothing to filter.

Here is the documentation on the filter: https://xtemos.com/docs/basel/faq-guides-2/how-to-create-filters-form/

Here is demo for filters: https://demo.xtemos.com/basel/product-filters/

You can use default Woocommerce filters.

Best Regards