Hi Sarah,
If you have find a filter to mount to the lens then you are well on your way. You will also need software like Paint shop pro or Photoshop. When you shoot through a filter like a Hoya 72 or B+W 92 the resulting image will be tinted red. To make a black and white image you will need to desaturate the image to remove the red or use the channel mixer to make the adjustment. If you need more of a tutorial let me know and I can provide a couple of links. Also if you shoot through a filter you are going to need a tripod. The filters are opaque so you need to frame the shot before you put the filter on. Then place the filter on and let the camera determine the exposure and shoot. I know it sounds like a lot to do and it is. But it will get easier as you do it more often.

Bobby