First take, out the battery, the remove the bottom plate. If you dont take out the battery you might destroy something when you pull away the bottom plate. Once inside you can see a white piece of plastic in the upper end (opposite of the end where the battery is located) off the Wah-Wah. This piece is what stops the little thing that goes up and down from sliding away from the inductor. Loosen the screw and push the White plasticthhing aside. Now you can move the inductor and thats how you choose from where to start and where to stop. I dont know which direction does what.. but just plug it in and try. Also be careful not to push the Wah to hard if it stops halfway down cause then you have changed the inductor to far, so before putting it together again check so you can move it all the way up and all the way down.
Hope this helped..
// Jacob