where do i start to ajust the mixture screws

can somone tell me how i should go about getting the adjusted properley on a 1978 kz1000 b2

Well, assuming you have stock VM26 carbs, then there is only a single screw (on each carb) that is adjustable, and this is the pilot air screw. If your bike has never been adjusted, then there might be a plastic cap covering the slotted head of the pilot air screw. If so, then you'll have to remove this cap...tighten the air pilot screw till it is lightly seated and back it out 1 1/2 turns. This is a good starting point. If you have non-standard carbs, it will depend upon what you have on the bike.

Edit: If you are speaking of changing the mixture jets, I strongly encourage you to get a Kawasaki shop manual for your bike, figure out what carbs you have, and then decide if you actually need to change jetting based upon what exhaust system and air intake system you have.