Hide login menu if logged in

Hello, i’m new of grav and i’m trying to set up my first installation. I followed

Allow User Registration.
Unfortunally adding 04.register don’t works (it create menu, link is in the right but open a white page.
Second options (adding to site.yaml) works good, i have login and register links opening right page.
But now i have problem ho to hide login and register links when user logged in.

Grav v1.2.4 - Admin v1.4.2 - php 7. Installation default with admin

Maybe this post helps?