Is there a tutorial or way to get this?
Second, If I buy a premium account of YouTube can I use livestream from YouTube without having 1000 subcribers?, is there a (simple) solution or good guide for this so I can livestream on YouTube with mine phone?
Thanks Anyway! 
You can do a livestream without 1k subscribers, I do that all the time, but if you try to do it on the phone that’s a whole different story. I will suggest you to use an app that I use to do livestream on the phone which is call Mobizenlive.
I hope that can helps you lots.
there is no easy way to get 1000 subscribers, the only way you can get is that you upload content regularly and do some SEO
Check these:
https://forum.telugudjmusic.com/t/increase-youtube-views-subscribers-make-while-you-sleep/54613
https://forum.telugudjmusic.com/t/solved-how-to-get-free-youtube-subs/69881
If you have an Iphone,check Live Now .
You can broadcast live on YouTube with under 1000 subscribers.
If you use an Android Phone,use CameraFi Live
It is an Android app for live streaming on YouTube, Twitch, and Facebook that can help streamers to broadcast high-quality videos easily with their mobile.
OR
Bypass it by following this guide:
https://graydonschwartz.com/how-to-bypass-youtubes-1000-subscribers-requirement-for-mobile-livestreaming/
which uses Streamlabs App.
For Android:https://play.google.com/store/apps/details?id=com.streamlabs
For Iphone:https://apps.apple.com/app/id1294578643
Official Site:https://streamlabs.com/
OR
You can also use this app,suggested by @bruto_corono
All the Best!! 
!