menu links

Hey! I really wanna have an extra menu in the topbar and have already put this code into the php:

$defaults = array(
   'menu' => 'Translation',
   'menu_class' => 'wptb-menu-class',
   'container_class' => 'wptb-container-class',
   'echo' => 0
);
$menu = wp_nav_menu( $defaults);
echo preg_replace("/\r\n|\r|\n/",'',$menu);

And it works fine! It’s just that all the links are listed below each other! I really want them to be beside each other. Any suggestions?

I’m using the theme twenty sixteen.

Thanks in advance!