A few more hopefully helpful comments

utils/ioda_example/gdas_meanioda.cc

@@ -4,6 +4,8 @@
 // this is an example application that
 // will use IODA to read a file and print something
 // it is intended to be very bare bones
+// you will note the .cc file is very empty
+// the .h file is where the action is!
 
 int main(int argc, char ** argv) {
   oops::Run run(argc, argv);