Following video show step-by-step construction of the Box Lifter. a. Construction of Frame of Box Lifter: https://youtu.be/cZW8XBk8rIk b. Construction of Carriage of Box Lifter: https://youtu.be/Fv3wrJbDjI0 c. Mates between Frame and Carriage in Assembly: https://youtu.be/S65Zhwavklk d. How to Drag the Carriage Up and Down https://youtu.be/ibixQJ5Nwm4