The Bmad manual has an explanation of the simple_bmad_program.
See the chapter titled:
  An Example Bmad Based Program

In brief:

To run the simple_bmad_program using the prebuilt executable that is contained in any Release or 
Distribution use the command:
    simple_bmad_program
[Make sure you are in this examples/simple_bmad_program directory] 

To build your own exe and run it:
  0) Read the "Compling Custom Programs" page on the Bmad site.
  1) Outside of any Distribtion or Release, create the directory:
      root_dir     (or any other name you want)
  2) Make a sub-directory
      root_dir/first_program_dir
  3) Copy all the files in this examples/simple_bmad_program directory into the first_program_dir directory.
  4) Go to the first_program_dir and issue the command which will compile and link the executable:
      mk
  5) Run the program:
      ../production/bin/simple_bmad_program


Notes:
  * If you are using a Bmad Distribution (as opposed to a "Release"), Make sure that the Distribution has
been built first! Directions are on the "Offsite Bmad Setup" page on the Bmad site.