Notification with value of a entity

Hey everybody, i tried to write a Automation, that gives me the Travelltime every morning.

I tried a notification:

service: notify.mobile_app_christians_iphone_2
  message: "Die Fahrzeit beträgt heute {{state(sensor.here_travel_time_hannover_duration)}}"

but i get an Error, sensor not known. sensor.here_travel_time_hannover_duration is an entity from the here integration.

what is my fault? Where can i find a documentation how i can mix Text with sensor values for notifications?

Thanks a lot!

Hint: Try it out first in Developer Tools > Templates
{{ states(‘sensor.here_travel_time_hannover_duration’) }}

Templating - Home Assistant (

perfect, i tried so many day and it was so easy with your link. Thanks a lot!