Remove the battery, take the blade back off and you will see the holes for the torsion spring. what you will have to do is start putting lower guard on but pretenstion the spring so it will fit back into the proper holes, it might be a benefit to remove the small bumper so that you can move the guard more. when installing the blade you don't remove the lower guard just retract it and slide the blade in place. Usually there is a retaining ring to hold the guard in place but I looked at a breakdown and didn't see one. Let me know if you need more assistance before voting please. Thank you