Drupal 8.x

Hello everyone,

I'm developing a website which has a big information architecture with several divisions and links. This information architecture is built inside the main menu. In the main menu, I will show only from level 1 to 3, that's already done. But I have another problem: I have a content type which is named "Institutional Section", and it is the majority of the menu links. I need the following to happen: when the user enters in an institutional section node which has sublinks, it should display a menu with the sublinks, and nothing else.

There is drupal 8.6.10 and i installs ubercart 8.x-4.0-alpha5. After module enabled in admin i get that error when trying to access /admin/config:

Uncaught PHP Exception Symfony\Component\Routing\Exception\RouteNotFoundException: "Route "uc_credit.settings" does not exist." at /.../drupal-8.6.10_new/core/lib/Drupal/Core/Routing/RouteProvider.php line 2

Does anyone know how to fix that?

In f.e admin/structure/types/manage/page/display there is at the bottom of the page:

I'm trying to make a site in 2 languages, German and English.

In Drupal 7, I used to make a multilingual menu with different URIs for the basic pages, different blocks and that was it.

Drupal 8... nightmare.

I went to language options and enabled everything I could, but then in the menu there was no way to specify different URIs per language.

Then I checked if I could create separate german and english menu items, hoping that the menu displayed in german would not display english items and vice-versa, but horror - everything gets displayed.