Click on the pencil tool in the toolbar and then click on the symbol button in the object type palette. Click on the symbol button again to open up the symbols palette. Click on Adjust to open the adjustable symbols palette. Click on the crescendo, the third symbol in the third row of the palette.
Now click and hold down the left mouse button where you want the left edge of the crescendo to go. Keep the mouse button down and drag the mouse to where you want the right edge of the crescendo to go.
Release the mouse when you have positioned the crescendo approximately where you want it. There will be three little diamonds at the left, right and center of the symbol. You use these control points to further shape and move the crescendo. Click on a control point to select it and drag it around to shape or move the crescendo. Alternatively you can move a control point around using the arrow keys. You can move between control points by using the TAB and the SHIFT+TAB keys as well as by clicking on them with the mouse. The middle control point is used for moving the crescendo and the outer control points for setting the start and end points of the crescendo. When you are finished shaping and positioning your crescendo, click the right mouse button or press the ENTER key to enter it into the score. If you don't want to enter your crescendo, press the ESCAPE key.