updates to 2d ocean example

source/Paraview/Colormap/transparent-clouds.rst

@@ -15,8 +15,11 @@ Now go to the color map editor
 
 Delete the center point in the bar with the color gradient (saves the effort of setting it to white).
 
+Activate manual editing of the transfer function (the gear at the bottom of the colormap display, here shown for a different colormap).
+
 ``Enable opacity mapping for surfaces`` in the checkboxes below the bar.
 
+
 Set the R/G/B values to 1 in the ``Color transfer function values`` section, and reduce the maximum opacity to 0.8 in the ``Opacity transfer function``. Play with the opacity value to find your favorite compromise between visibility of clouds and background.
 
 Things should now be changed from