well I buy first infinite edge, because I have attack speed buying the black cleaver, and Cait need to get a lot of damage to push fast at bot lane, I try to change the order of items but I prefer this order, is more easy to get more expensive items.

when you has the first 3 items you are unstoppable, you only target is "capture the bot tower, or to be very troublesome making that one or more enemies have to go out of his lanes"

I'm sorry for my noob english, I try to explain the more I can.

thank you for your comment.

Except that i would prefer phantom dancer BEFORE buying infinity edge (crit chance BEFORE crit dmg) and put the 2 points at offensive mastery not in dmg to minions but in CDR, this build looks interesting. will test it.