Hi Mamadou,

1—You can use Breadcrumb NavXT plugin to enable that functionality. When you install the plugin please make sure to add this code in the functions.php file of your theme too:

add_action( 'kalium_header_main_heading_title_before', function() {
    if ( ! function_exists( 'bcn_display' ) ) {
        return;
    }
    if(!is_front_page() && !is_page('home-business')) {
        echo '<div class="container"><div class="site-breadcrumb">' . bcn_display( true ) . '</div></div>';    
    }
} );

so the breadcrumbs will appear. Then you can tweak the options of the plugin to fit your needs.

2— You need to use Taxonomies area to filter a product category as we explained in this article.

Have a nice day!