Aside all the "next expack" doomsday threads i have some simple question about that tool that help a lot of people to optimise theyr toons

Can someone explain what does the fight style "HelterSkelter" is like? Like maybe give example of such fights.
Can someone tell what is the diffrence between "Patchwerk" and "Ultraxion" fight styles?
Does the "Target Race" have any meaning (exception trolls and maybe orcs)?
And last but not least - what are these "Plots" and "Reforge plots" for?

I cant really understand the explnations for plots from "Welcome" page. some clarifications will be appreciated