HASS as Alarm Clock

How can I use HASS as alarm clock that performs certain tasks and plays certain message on my mobile device at sunrise?

I don’t know what you mean by play messages (push or audio?) but you can create a simple automation with the sunrise as a trigger.

description: "Do things at sunrise"
mode: single
  - platform: sun
    event: sunrise
    offset: 0
condition: []
  - service: notify.notify
    metadata: {}
    data: {}
  - service: media_player.play_media
    metadata: {}
    data: {}

That should help you start. Import the code as yaml in an automation then switch back to visual.

A little extra:
If you want to send a push msg and play a custom sound:

service: notify.mobile_app_yadda
  message: WAKE UP
    channel: alarm

Like this your phone (android idk about ios) has the option to set another ring tone in the setting for this category.

Thank you for the reply. Actually, it is audio message.

Before I try the automation you provided, how to make it trigger 30 minutes before sun rise?

Set to offset to -00:30:00.

So, I should use minus sign.
Speaking about audio output, how can i make it play text-to-speech on the device?

There are plenty of threads about that already on here.

Ok. I can manage that. Thanks.