What do I need to do to get Eureka Weapons?

[VirusChris]

Alright I haven't even started to work on getting any of the Eureka Weapons as I was busy leveling up my other classes and have been on break for months now. Came back and want to at least finish Eureka a bit.

Basically the story and weapon. But the place is sort of... not interesting me? It's so slow and such, but I did have fun with other people.

That said I only unlocked Pyros I believe was the name of the second area and I'm only level 17 - 19 last I remember so I got a ways to go.

I know they've done updates to nerf the grind a bit, but I do recall one of the steps causing your previous stats you added to the weapon to be reset so it's kinda pointless to do.
Also what changes to the steps as well so I know what I'm getting myself into and not making a mistake somehow while trying to make one Eureka weapon.

What do I have to do for each step so I can make this as easy as possible for me? I currently have 80 Protean Crystals and 912 Anemos Crystals and apparently I'm set to get the items for the weapon asap.

I'm going for NIN as it's my main. So what's the three stats I should focus for it?