Add 'Run DART with your model' documentation

guide/adding-your-observations-to-dart.rst

@@ -1,2 +1,21 @@
 Adding your observations to DART
-================================
+================================
+
+First, you should understand that DART already supports a tremendous variety of
+observations. To fully support an observation means that the observation can be
+converted from its native format to the DART observation sequence format and
+that the observation forward operator is already implemented. Keep in mind that
+forward operators are not specific to any one model.
+
+The observation converters are in the *observations/obs_converter* directory and
+you should look there for the documentation describing which converters are
+available.
+
+The forward operators are functionally or logically grouped into Fortran modules
+in the *observations/forward_operator* directory. DART employs a ‘contractual’
+style of programming in that the forward operator requests information from the
+model, and if the model cannot provide it, the forward operator may request
+different information in an attempt to collect the information needed to apply
+the operator. If the model cannot provide any of the required information, the
+forward operator fails, the DART QC for that observation is set to the
+appropriate value, and the program continues.

guide/how-to-test-your-model-mod-routines.rst

@@ -1,2 +1,10 @@
 How to test your model_mod routines
-===================================
+===================================
+
+The program ``model_mod_check.f90`` can be used to test the routines
+individually before running them with *filter*. Add a ``mkmf_model_mod_check``
+and ``path_names_model_mod_check`` to your ``DART/models/your_model/work``
+subdirectory. You might find it helpful to consult another model matching your
+model type (simple or complex). See the documentation for ``model_mod_check`` in
+``DART/assimilation_code/programs/model_mod_check`` for more information on the
+tests available.