REALLY getting started with pixel bender?

I have a problem getting pixel bender to run within after effects.
i've been trying to figure this out for a while by myself now, but for the life of me i can't seem to get it together.
i installed it and have an application to make plugins. great.
i also find a few basic pixelbender effects in after effects.
But what i really want to do is use the great plugins that others have made!
But if i download some new pixelbender plugins, i have no idea where to place them to become active in after effects.
I've tried in the plugins folder, in the adobe utility folder and a bunch of other folders, but no dice.
So now i have a few folders with pixelbender toolkit and pbk and pbg files in it, but none of the once i've downloaded show up.
And all i can find on google is how to make new plugins or how great pixel bender is.
Am i really that dumb?

dear community, please help!!
Henk

that works!
i have been trying to install them in various folders, both pixelbender toolkit follder, cause that is the one that seems to have the sample pixelbender plugins in it that show up in after effects. and in separate pixelbender plugin folders that i made myself. But i never came up with the rather simple idea that you could just throw them into the actual plugin folder itself. ha, so i guess i really am that dumb:-) What still baffles me tho is that in my dropdown menu in ae there is a pixelbender category with only the samples plugin in it, but that the new ones i found on aescripts for example show up as their own category. but hey, that's of minor importance. They work!! thank you for enlightening me!
Henk