Once we have created the panels, we need to do a bit of modification on them as you can see that they overlap.  For better visibility of the design, you can turn off the visibility of the skeleton (blue surface).  As you can see there are also options to turn off the visibility of all panels and any bodies that have been created.

The Trim function works very much like the AutoCAD trim function (to my mind).

You select the panels that need to be shortened, and then you select the panels that will be the boundary of the shortened sides.

If you just select a panel and do not select any boundary components W4I will assume that you want all the panels touching your soon to be modified panel to be the boundary components.

The Miter command will cut the panels at a 45-degree angle.

Another commonly used method to modify the panels is to use the direct edit feature.  This command is native to Inventor and very useful for directly editing models that you might have imported from an external source.  You can either move a face or move an entire body/panel.

To use the command select the Direct Edit button and then choose whether you want a body or face to be selected.

You will now grab the arrow and drag it to start the move process.  You are also able to enter a value both negative and positive.  If you need the face or body to snap in line with another plane or face you can utilie the snap to command on the dialog box.