Hello guys
The story is that I just bought a Kindle Touch 4th at the Facebook marketplace and it seems to have been blacklisted so I can't register for an Amazon account. So I tried to find a way, and luckily there was a way to help it: jailbreak.
Jailbreak is pretty great as it can help me install some external applications and change the old Kindle's interface and lock screen, but you know I don't have any experience with this at all

So can you guys show me how to jailbreak and install Koreader (it would be great to add Sudoku)

My Kindle's Serial is: B010xxxxxxxxxxxx
- Firmware is: Kindle 5.3.7.3
Thank you guys in advance <333333