Shopify to Woocommerce product attributes not linked properly

Hi,
After importing from Shopify to Woocommerce, we noticed that attributes aren’t added in a way to be usable with Woocommerce product filters like color, size and brand.
The attribute is there but not linked to Woocommerce filtering system.

How do you suggest we proceed with this issue? Is there a plugin or fix for this issue?

Kind Regards,
Amplus Dev Team