Inserting a reference plane

Hi guys.
I'm new to MasterCAM but know Solidworks and ACAD pretty well.
I'm trying to increase my skill level for MCAM and would like to know how to insert a reference plane at an angle to a surface to produce a cut profile. For instance, I have a block of steel that needs a square pocket in it. The bottom of the pocket needs to be 30 degrees from the top. How can I easily draw the shape and then use FBM to cut it? I can import a solid but would like to learn how in MCAM.

Hope you understand the question as its hard to explain.

Thanks
Yoda

Are you asking how to to create a plane to program it at 30° rotation or to draw it in MC? also what version of MC are you using?