The section on the Bank CNC training website listed below has a thorough tutorial you should follow along to for creating surface toolpaths in MasterCAM.
Rhode Island School of Design
Department of Furniture Design
semester: Spring 2018
FURN-2511, Sections 01 & 02 (3 credits)
2nd Floor of Prov-Wash Building, Room 202 and 237B
Mondays, 1:10pm – 6:10pm
instructors: Christopher Specce, Cutter Hutton view the syllabus