On the right side of the machine you'll see the circular chain adjuster, with part of the handle laid flat. Lift out the handle (through 90 degrees) and slacken off by turning anticlockwise a couple of turns. The spring adjuster will auto-tension when you move the bar a little. Re-tighten the circular lock and park the handle flat again. Job done. No tools needed. :)
Pete, January 2011