Before running an MPI program, place it to a shared location and make sure it is accessible from all cluster nodes. Alternatively, you can have a local copy of your program on all the nodes. In this case, make sure the paths to the program match.
Run the MPI program using the mpiexec command. The command line syntax is as follows:
> mpiexec -n <# of processes> -ppn <# of processes per node> -f <hostfile> myprog.exe