We don't have a tutorial for how to do this using MySQLi
you would need to create the search form, then edit the recordset to add the filtering.
set the search form to use the GET method. the create URL variables for each of the form elements using the same name as the form elements.
Go to the bindings panel, click the plus button and select URL variable. set the url variable name to the same as the form elements, repeat this for each form element.
Now edit the recordset, using the advanced MySQL Query Builder you can add conditions to the where clause to filter the category using the category URL binding and the state using the state URL binding.