start by placing the pin holder in the bottom of the box and place the fake floor on top of the spacers, when the pin-holder is at the bottom the pin should be about 1 cm below the surface of the fake floor, and when you pull the push rods the tip of the pin should be about 1 cm above the surface of the fake floor. if this is the case glue the fake floor to the spacers and the sides of the box, if not make it so. if you wart to be 100% sure it works you can make a little test (see video)
next make 3 "gliders" they are made by cutting a piece of cardboard about 7 cm wide and the hight of the box and make 4 bends width wise(see pic.) next glue them on to the sides over the push rods.