Load the appropriate mpi/openmpi module for your chosen compiler. Compile your code using the OpenMPI provided compiler wrappers: mpicc, mpif90, mpicc++, mpif77. 

To run your code on the workstations use the mpirun command. Most people probably just want mpirun -np 2 ./my_program. If you are lucky enough to have access to two or more PCs to run on have a look at the manpage for mpirun, or try mpirun -np 4 -H pc1,pc2 ./my_program. You will need to have set up passwordless login from one PC to the other using ssh public key authentication.