Select the line tool and press to open the settings.

Select 'Sharp Edges' from the type menu.

Choose the thickness of the line using the 'Thickness' slider. The higher the number, the thicker the line.

When you are finished with these settings, press the 'Done' button.

Press and hold the spacebar or to begin drawing.

Use to move the cursor around the screen creating your line. When you are finished release the spacebar or .