Hello @padel,
In order to use the filters, you must understand and create variable products on your site. Variable products require different variations based on the attributes, so you must first create the attributes and then assign them to the variable product. After that, you will be able to filter the products based on those attributes.
We have recorded a video for you on our test site. Please watch it in its entirety and follow the steps shown in the video: https://www.veed.io/view/27f63b7e-4069-41cd-b8ba-7f3a523b81d3?sharingWidget=true&panel=share
In addition, please refer to the official documentation of WooCommerce: https://woocommerce.com/document/variable-product/#:~:text=Variable%20products%20in%20WooCommerce%20let,small%20and%20in%20different%20colors.
We hope this helps!
Best regards,
8Theme’s Team