If it has a screw on the bottom of the forend, remove it, then pull the forend away from the barrel, same if it doesn't have a screw, it may just snap on and off, it may be very tight so it will take some force, I've use a wood block and a hammer to remove some that were real tight, place the block against the top edge of the forend on one side near the muzzle end and tap it so it pushes the forend directly away from the barrel, it will pivot around the frame and come right off.
Tim