Counter Knight Opening

I have been playing against a lot of knights attacks with is when the bishop gets brought out and the knight tries to do a fork early on. I have no idea how to counter it though. Can someone give me some help on this?

It depends on the specifics, but having certain patterns in mind is the key so you have an idea what to look for. Sometimes:

-we can play a pawn advance to cut off the Bishop and Knight (...d5 at some point here to cut off the Bishop and Knight coordination on the f7 square)

-we can castle to protect the King (and the castled Rook would be on f8 to guard f7. 

-we can play a prepared line; in this case, the "Polerio Defense" is probably the refutation to the Italian Game Knight Attack, but this Polerio Defense is sharp and tricky; some people aren't always willing to sacrifice one or two pawns for Black's counterattacking chances, but it is solid and I use it to good success. This Polerio Defense takes some chess study though. The start of this line is 4...d5 5. exd5 Na5! temporarily sacrificing a pawn and sometimes even gives up a second pawn in some lines, but the active play Black gets is dangerous.

This should get you started in the right direction if you want to try this opening line for Black:

https://www.chess.com/forum/view/game-analysis/how-did-black-lose-the-initiative-what-are-some-key-factors-i-mis-evaluated-or-failed- 

Oh boy, it's sharp and complicated leading to Fried Liver and Traxler Counterattack.  U'll need several years to study all that.

lol Yeah but the op doesn't need to become masters in every variation of the Italian Game; they just have to pick a few lines to use themselves and study those. For example, if you study the Polerio Defense lines I recommended, then you don't need to learn the Fried Liver or Traxler Counterattack in detail because those are different variations that we avoided by choosing our line.

Ok , in the case of Polerio defense, it would be something like that (Bishop Check Line):