After entering Utility usage information (instructions on how to enter utility usage can be found here), you will be taken to the system page 
to design the system.
Click + New Solar Array
You can create an array by drawing the array, or by entering the data without drawing. In this example, we will draw the array.
Click Draw Array
Use your mouse to outline the area where panels will be installed.
Next we select the azimuth by mousing over the lowest edge of the roof.
Clicking on the green edge will set the azimuth angle.
Click Done.
The Array window will appear with the azimuth auto-populated.
Select the desired module and inverter and click Fill Array.
The array will appear in the image, and basic system information will be shown below the system tab.
Nice work creating a new system!
Click Quote This System to proceed to the quote page.
Instructions on how to create a quote can be found here.