If I only have American keyboard settings on the laptop, how do I download the German keyboard settings?

If I only have American keyboard settings on the laptop, how do I download the German keyboard settings?

It does not work.

How so?

Because the American keyboard does not have all letters such as the "ß", the "ä", the "ö" and the "ü".

I have no idea which operating system you are assuming, but something like country setting, localization, keyboard layout etc. Must be found in the system settings.

In Windows 10, this should go through the setting of the region