add basic scaling test instruction

README.rst

@@ -225,3 +225,28 @@ Detailed full installation instructions:
     In case these files provide incomplete information, it is necessary to update
     the cmake input config file: turtle/cmake/TurTLEConfig.cmake.in.
 
+--------------------
+Scaling tests.
+--------------------
+
+Initial scaling data is available at <insert url here>.
+Please copy the files to the location `TURTLE_FIELD_DATABASE`.
+
+Separately, please recompile TurTLE after appending "-D USE_TIMINGOUTPUT" to the `TURTLE_COMPILATION_FLAGS` environment variable
+
+Afterwards, please run variations of the following command:
+
+    .. code:: bash
+
+        python ${TURTLE REPOSITORY}/tests/DNS/test_scaling.py D \
+            -n 128 \
+            --nprocesses 4 \
+            --ncores 1 \
+            --src-wd ${TURTLE_FIELD_DATABASE} \
+            --src-iteration 8192
+
+Available iterations for
+
+    * n = 128: 8192
+
+