A box sits at rest on a rough 30 degree inclined plane,
a)draw free-body diagram,showing all forces acting on the box.
b)how would the diagram changes if the box were sliding down the plane?
c)how would it change if the box were sliding up the plane after an initial shove?

Start by listing out the various forces acting on the box. For example for (a) since the box is stationary you know all the forces must balance - what are these forces? List them out here, and we'll help you if you need it.