To change the flint you will need to remove the glass from your lamp. Unscrew the flint housing cap and the flint spring. If the flint does not fall out then unscrew the flint wheel button, the slotted brass screw head which holds the flint wheel onto the spindle. Grip the flint wheel with pliers ,then using the screw bit from the kit in a bit holder carefully unscrew the flint wheel button. Lift off the flint wheel making sure to check which is the top. Push the flint out with a pin or fine drill. Replace the flint wheel and button, do not overtighten. Put the new flint in the housing, put the spring in the housing cap, screw the cap into place, finger tight only. Test the spark ,if necessary finger tighten the housing cap until you get a shower of sparks.