How To Make ADM Weapon

Hello Guys i have one question becose i couldnt find detailed explain about making new weapon.

so far i know i have to modify game_server.evp (repacked) in

local/common/table/item.csv = items
local/common/table/model.csv = model items
local/common/table/item_suit.csv = purple items
local/mars or malay_gb/language/item_desc.csv = to give items name

but can anyone explain me what to change and what i must not touch pls becose there are about 18 collums in each .csv

I would love it if anyone could answer or give me youtube link.

I have one more question btw.
I modify upgrad +20 to be all +100% but ingame succed rate doesnt show up its +100 just untill +7 (ingame) but after it work as i set 100% but show like +10 1% succed rate,but always succed because i made 100%

so can anyone tell me file to change blacksmith upgrade succed rate

sorry for bad english hope you understand what is my problem.