Use the Line Segment tool when you want to draw one straight line segment at a time. For a video on using the Line Segment tool, see www.adobe.com/go/vid0036.
Position the pointer where you want the line to begin, and drag to where you want the line to end.
Click where you want the line to begin, and specify the length and angle of the line. If you want to fill the line with the current fill color, select Fill Line. Then click OK.