A practical example is provided in oasis3-mct/examples/tutorial reproducing the coupling between two simple codes, model1 and model2, with OASIS3-MCT.
See
the document tutorial.pdf there in and the on-line
tutorial at
https://verc.enes.org/oasis/oasis-dedicated-user-support-1/user-toys
/tutorial-and-test_interpolation-of-oasis3-mct-1 for more details.