On the Design page within a project click Insert Panels.
Select Modules.
Select the module type, orientation, tilt, rotation, and spacing.
Make sure to set the rotation to 180 degrees, or whatever is appropriate for your design.
Click the Fill Roof Face button.
Click on the roof to place the system.
To Toggle into 3D Mode:
Click on the 3D cube (or hold right-click) and move your cursor down.
You can view/hide setbacks and toggle on/off the map imagery in the top toolbar.
To Make Adjustments to the System After It's Been Placed on a Roof:
Click and drag a box around the panels with your cursor.
In the toolbar on the right you can make adjustments to the orientation, tilt, rotation, or click the Auto-String button to string the system to an inverter.