Pause the cursor over a corner of the ViewCube. Click a corner to switch to a different isometric view.
Click an edge to switch to an edge-on view.
Click a face to switch to an orthographic view.
In an orthographic view, the Z-rotation arrows are available and provide a rotation axis normal to the screen. The axis passes through the geometric center of the model. Click an arrow to rotate the model 90 degrees.
Also in orthographic view, the program shows arrows to select faces adjacent to the displayed face.