I Pre-ordered the the game on amazon for my PC. and I don't know how to get my dlc. any body know what to do?

Contact amazon. They will be able to help you.

Definitely contact them. I'm from Canada and pre-ordered from the US (because Amazon.ca for some reason didn't carry the bonus pack).
I got my email with the Psycho code in it recently.

If I, ordering it internationally, can get the pre-order pack, you should be able to too.

Probably i think he doesn`t know how to use the Code on Steam.

yeah i dont know how to use the code on steam. even if i did get it or know where to look for it.... srsly i dont know where it would be