DJM 850 + Traktor scratch setup?

Hi everybody -

i can't fix my problem even if i look through all this posts and manuals.

I want to make a setup for

2xCDJ 850, 1 CDJ 850 Mixer, and Traktor 2 scratch timecode.

I found a video about the setup for a DJM 900. But it must be a different way.

I use a Macbook with yosemite. Can anyone give me a link where i can found some informations for a right setup? THANK YOU !