My first Sony Phone.. how to get the basics done?

Could someone give me a super quick guide on how to get this on my phone? I coming from years of Samsung phones and never owned a Sony before or know anything about it. I have CM on all my Samsung devices for years and simply want a CM ROM in the Z and get it done with with. I picked up a 99% like new second-hand Ultra Z LTE C6833 today, has stock 5.02 and I don't have a clue how to get this flashed in the easiest and simplest way possible. As for locked or not bootloader, I also don't have a clue. First step which is to install TWRP I immediately got stuck because the links posted are dead (teamw.in/project/twrp2/219)

Without wanting to waste anyone's time, if someone could give me the simplest and most painless info on how to get the Z flashed, I'd be super appreciative. The threads on this phone are in the hundreds at this point and I read all sorts of very confusing and contradictory info. I worry to kill or brick it immediately before I even get started.

Thanks much in advance:)