Updated help text

app/scripts/help/help.directive.html

@@ -29,7 +29,7 @@ <h2>Features</h2>
       <p>The time bar on the bottom is used to define the time you want to see data of. it is automatically scaled to the extents of your selected dataset.</p>
       <div></div>
       <b>The graphs on the left</b>
-      <p>The graphs on the left side appear when the user clicks a location on the map with sufficient time-based data. The graphs initially both show the globally selected dataset, but can be set to a different dataset.</p>
+      <p>The graphs on the left side appear when the user clicks the button to display them. Clicking a location on the map with sufficient time-based data will then display a graph of the data in that location. The graphs initially both show the globally selected dataset, but can be set to a different dataset at will. The graphs also include a log checkbox, to set the vertical scale to a logarithmic one if desired.</p>
       </div>
     <h2>Troubleshooting</h2>
       <p>If you can only see a globe with normal coloring, and the dropdown menus at the top seem suspiciously empty, that probably means you have no ncWMS server attached, or that server is serving no data at the moment. Please refer to the README file.</p>