Another Shop built taper jig
AS far as instructions, layout the angles on the workpiece, adjust the jig and measure so that the distance to the fence is the same at the front and rear, creating a parallel cut. Then make the pass.
Next step is making the other side of the workpiece the same and requires resetting the angle on the jig since there is now an different angle sitting against the jig. This jig can be flipped on either side since the adjustment is on the end. The other end is just a simple hinge.
The answer to your question will only be as detailed and specific as the question is detailed and specific. Good questions also include a sketch or a photo that illustrates your issue. (:< D)