How can i list the categories of a post type, the taxonomy

This should get you started

function my_cpt_cats() {
    $parent = get_term_by( 'slug', get_query_var( 'term' ), get_query_var( 'taxonomy' ) );
    $args = array(
        'type'                     => 'post', 
        'child_of'                 => $parent->term_id,
        'parent'                   => '',
        'orderby'                  => 'slug',
        'order'                    => 'DESC',
        'hide_empty'               => 1,
        'hierarchical'             => 1,
        'exclude'                  => '',
        'include'                  => '',
        'number'                   => '',
        'taxonomy'                 => 'YOUR_TAXONOMY',
        'pad_counts'               => false 
    );
    $categories = get_categories( $args );
}

Remember to use your taxonomy name in the $args array.