Your question has been translated to English as this is an International forum, please post any replies in English.
In Android 9.0 (Pie), the volume keys will only adjust the media volume. This is different from previous versions of Android, where ringtone volume was the default setting. There is no way to change this setting in Android Pie. However, there is a toggle button for the three ringer modes just above the on-screen volume slider, which lets you turn the ringer off and on with a single tap. During calls, the volume keys will adjust the speaker volume for call audio, and the on-screen volume slider will show an additional column for this.
There may be third party applications that allow you to change the mapping of the volume keys.