New Kindle pw5 6.8

[micione20]

New Kindle user,
after 10vyears of kobo glo jailbroken.

What should i do, to Active and turn on device without internet, check firmware and see if it is jailbreakable? What firmware can be jailbroken and how? And how block updates?
And what can do with jailbreak (on kobo there were hundreds of patch to activate with a Simple notepad script)


Thanks for your clarification
--------------------------------------------------------------------------------
Edited
Done:
jailbroken 5.15.1.1 with language exploit
installed kual
installed Mrpi
installed kual+
disabled OTA updates
installed koreader

Thanks