Choose the arrow tool in the toolbar. Double click on the upper left edge of the beam group you wish to adjust and select Adjust Beams from the Edit menu that appears. Two handles will appear. Drag the beam up or down by dragging the left handle up or down until the beam is where you want it. Drag the right handle and the angle of the beam will change accordingly. When you have positioned the beam so that it is as you want it, press ENTER or click the right mouse button to complete the operation. To cancel the adjust operation, press ESCAPE.