Breather Filter/Confused!!!!, Simple explanation please.... Options

[TRD_GT]

Ok,i've read every topic on here in relation to breather filters,PCVs and how all this works,how to fit the breathers etc etc..one thing..i have never been so confused in my life, every topic has a different explanation, so my fellow celica owners,please for the love of God,someone just give a simple description on how to fit a breather filter and if its worth it..

I've just fitted a K&N Induction kit to my GT,i've done all the correct fittings,Air sensor,PCV and that other tiny hose thing are all fitted in the correct places,only thing is, i have a breather filter..i was just wondering, is it even worth fitting this thing or not..if i do..shall i just plug up the hole in the intake pipe and leave the filter to do its thing or am i just being stupid?

Whoever gives me the simplest explanation may you have the fastest car in the world..