The complete lecture on forces.... along with some practical worked examples to help you with your tutorial.... will be online soon
The "Normal" force is PERPENDICULAR to the (inclined) SURFACE..... as shown below....
and the COORDINATE SYSTEM is tilted so that the x-axis is ALONG THE INCLINED PLANE
(the reason for tilting is that it SIMPLIFIES the algebra for this problem)
the solution for the Forces is below: