DUDU-Meng He's asking for the ability to adjust android auto volumes independently, and to do it in a way similar to how it is in OEM units: whenever a type of audio is played (notification, alarm, call, etc.), you adjust the volume of that type as it plays, and it remembers your setting for next time you start android auto.
Let's say I'm listening to music using android auto and the volume is set to 20; if a notification plays, I should be able to adjust the volume using the steering wheel controls or directly on the unit, as to adjust the volume of notifications in android auto independently from media without navigating to any menu. The next time a notification plays, it will play at whatever volume I set it to, regardless of other volume settings for other audio types (alarm, call, media, etc.)
