how to add custom plugin menu link in toolbar

function ledger_manager_link($wp_admin_bar) { $args = array( 'id' => 'ledger_manager_link', 'title' => 'Ledger Manager', 'href' => plugins_url('ledger_credits.php'), 'meta' => array( 'class' => 'ledger_manager_link', 'title' => 'Ledger Manager Menu' }