Well, it's really difficult to generalize how the game works and put it short. There's some Guides on starting off in the official Guide section, however, I can't say I'd recommend those because the whole Guide section is being reconstructed because the guides in there are low quality and some even have some incorrect information. But as a first-hand experience on some general stuff about the game, it may serve well.
But don't worry, the game is very newbie-friendly and simple, you just need to get the hang of the basics and it will be smooth sailing from there, especially if you've played other MMORPGs before.
what build do i need? and items? and how to get that items. and i d k what is acc,con,agi hahahaha
Acc, Agi and Con are stats, you earn stat points which you can allocate to either Stat (pretty self-explanatory), this is what your build depends on - which stats you put and in what ratio.
Acc (Accuracy) increases ranged attack power (So the damage of SS) and Hit rate (The more hit rate you have, the higher the chance you'll hit your target)
Agi (Agility) increases attack speed (How fast you attack, self-explanatory) and Dodge rate (The more dodge you have, the higher the chance you'll dodge an attack)
Con (Constitution) increases the defense and health, basically makes your character more beefy, but it takes quite a bit of Con to notice the difference.
There's also Str (Strength) and Spr (Spirit), but those are useless for SS.
If you've read this or other SS guides here, then you may have learnt about Con SS, Acc/Con SS, Acc/Agi SS, Agi/Acc SS and so on, choose a build you like based on what playstyle you prefer.
and items? and how to get that items
When you start the game, you'll earn a yellow box in your inventory which you can open every 5 levels. It will give some basic Equipment (up until Lv45) to help you out. As you level up, you'll want to purchase Evanescence and later on Enigma Chests from other players, Unseal and Chaos Equipment. You'll learn about all of those as you play the game, but the point is, you won't be able to get the best Equipment from the start and you'll have to go through multiple equipment before you get to the best set.