When I selected a Generic 10kW wind turbine for a generation source, it places the wind turbine on the right side of the diagram (to the right of the load) When I switched to a Generic 20kW turbine, the turbine is now located on the same side as the grid.  Is there a switch somewhere that controls that?  (I assume on the left side the output is classified as AC, and on the right DC).

When you make a selection from the turbine type drop-down box in the Wind Turbine Inputs window, you are choosing the properties of the wind turbine.  Those properties include the power curve and whether the turbine produces AC or DC power.  You can specify AC or DC when creating a new wind turbine to add to the list in that drop-down box.  In the schematic diagram, HOMER draws AC turbines connected to the AC bus, and DC turbines connected to the DC bus.