Here are two web pages that will tell you everything you need to know about playing Killing Floor

Killing Floor Wiki: http://kf-wiki.com/wiki/Main_Page

Killing Floor Manual: http://files.thfnn.com/kf/kf/help/killing%20floor%20game%20manual.pdf

If you want to download the manual, then just go to: http://files.thfnn.com/kf/kf/help/
Then just right click on "killing floor game m..>" & "Save As..."