Ok so I have just finished working on one of my helms I do the usual stuff of getting it into the CS and setting it up as a helm. But when I try it on in game all it dose is make my head/hair disappear. Then I tried setting the bimp as one of the helm options but instead of being my helm when I put it on it is the one that I selected. If you guy's could let me know what I am doing wrong or what to do that would be great.

I assume you have set it first as a body part: "Hair" for opened or "Head" for closed helmets and used this slots in biped object in the armor window. Check male/female settings - male will be bald wearing female helmet.
Sometimes PC/NPC do not have sufficient abilities/class etc. to wear particular type of armor.
In general MW slots is still a mystery, I would be very happy to have a detailed description/table of clothes/armor slots and their compatibility e.g. for unclear reasons gloves/clothes/hands (or gauntlets/armor/hand) are not compatible with bracers/armor/wrists but work fine with pauldrons/armor/wrists.
Helmets are also not working for me without obvious explanations.

Ok I figured out what was wrong, you have to make a body part that go's with your item, all you need to do is use the nif that you made for that armor item, and use it when you make the body part item, then when you go to make the armor set the bimp as the body part you made.