added organization of westpa section in CONTRIBUTING.md
@@ -13,6 +13,16 @@ As a start, the following video discussions involving WESTPA development may be
Other resources include our [GitHub Issue Tracker](https://github.com/westpa/westpa/issues), archives of the [WESTPA developer's mailing list](https://groups.google.com/group/westpa-devel), and our [Sphinx page](https://westpa.github.io/westpa/sphinx_index.html) for API documentation of the WESTPA code from autogenerated docstrings. Please note our [Code of Conduct](https://github.com/westpa/westpa/wiki/Code-of-Conduct).
+## Organization of WESTPA
+
+**Figure 1 | Key steps of running a weighted ensemble simulation within the WESTPA framework.** Upon initialization of the WESTPA environment and trajectories, the simulation manager controls the execution of a weighted ensemble simulation, including dynamics propagation using a selected dynamics engine via the work manager.
+
+![Organization of Westpa](https://raw.githubusercontent.com/westpa/westpa/gh-pages/images/westpa_map_simple.png)
+
+- [HDF5 File Organization of Simulation Data](https://github.com/westpa/westpa/wiki/HDF5-File-Organization-of-Simulation-Data)
+
+- [Index of Command-Line Tools](https://github.com/westpa/westpa/wiki/User-Guide#INDEX_OF_COMMANDLINE_TOOLS)
+
## Guidelines
- All contributions are submitted by making Pull Requests, *even from developers who have write permission on the WESTPA repository.*
