the taper attachments will taper the hair, with it longer on the top and shorter on the bottom. Put them on the clipper then hold the thing to the side of your head that the thing is labeled for. It should be pretty obvious after that. The blending is used to blend two different lengths of hair.
Hairdressers/barbers don't use the taper one (I've never seen it) but the blending one gets used all the time, because I keep the sides and back pretty short.