The most essential literature to read before starting to code any McStas is

• The http://www.mcstas.org/documentation/manual/mcstas-manual.pdf McStas manual, chapters
  • 1 (General introduction - optional)
  • 3 (Monte Carlo introduction - optional)
  • 4 (On running McStas)
  • 5 (kernel and meta-language)
  • Appendixes A and B could also be relevant.
• The http://www.mcstas.org/documentation/manual/mcstas-components.pdf McStas component manual is mostly good to have as reference information. Chapter 2 is the same as chapter 3 of the ordinary manual.
• It may also be helpful to perform a few simulations as a McStas user - for instance via the McStas tutorial, available via the mcgui -> mcdoc menu