@PiotrBujakowski
Because there is no Ubuntu Touch port for your device.
https://devices.ubuntu-touch.io/

And Ubuntu Touch is not the same as "Linux Ubuntu" for desktop, you can't install it the same way, like I said, it need to be ported by someone, maybe you if you have skill for, but it's a long and hard job to be done.
https://forums.ubports.com/topic/2068/halium-first-steps

@rvan Now I understand. The "warning" is only alerting or reminding you that it needs your permission to access parts of your phone in order to do its job. It is nothing to be concerned about, so go ahead and install it.

Hi and welcome @jukhamil
Ubuntu Touch is not the only alternative OS out there but one we love and promote here.

About your device, I'm not sure it is currently supported.
You can head to https://devices.ubuntu-touch.io/ to see a list of supported devices and their progress.

If you want to get your hands dirty, you can try and port for your device.
These links are a good starting point:
https://forums.ubports.com/topic/4328/qa-checklist-for-ported-devices
https://forums.ubports.com/topic/2068/halium-first-steps

I moved your thread considering https://forums.ubports.com/topic/206/will-you-port-to-device-x

@jujubala1997 said in Help the community:

Where do I start? What are barriers that impede UT from spreading? What should I learn in software to help the community?

Depends your area of interest and confort : community, system, porting, coding, Art etc... and you don't even need to be good or educated in that field, like me 🙂 just learning by tweaking.

Python wise they are several possibilities :

full applications : https://github.com/ernesst/ActivityTracker Wrapper : https://framagit.org/ernesst/MLS-for-Utouch / https://framagit.org/ernesst/gps-utouch-tracker

Python get integrated into QML via : https://github.com/thp/pyotherside

A very nice python lib would be great to integrate into Utouch : https://github.com/owncloud/pyocclient for Nextcloud/Owncloud.

Welcome in the community.