Hey there! Thanks for downloading my rocket crawler instructions. To use these instructions, you must have Lego Digital Designer (LDD) installed on your computer in order to open the LXF file and generate building instructions. Once LDD is installed, open the LXF file and press "Building Guide Mode" at the top right hand corner of the window (or by pressing F7 on your keyboard). PLEASE NOTE: The LXF file is an APPROXIMATION of how my crawler was built, as, due to the limitations of LDD, there are some missing or swapped parts that differ from the LXF file to my real life crawler. Please refer to the photos included in this brickshelf folder (in the folder "points of confusion) - they show the correct pieces used which the digital LXF instructions may get wrong. Enjoy!